If there ever was a tie that perfectly depicted the complexities of team selection at the Davis Cup Final 8, Thursday’s quarterfinal between Australia and USA would be a strong candidate.

In a clash between two powerhouse nations in the history of the competition, Australia narrowly defeated USA 2-1 by clinching the deciding doubles at the Martin Carpena Arena in Malaga.

Both teams have deep benches with multiple options for singles and doubles, which sounds like a blessing for Australia captain Lleyton Hewitt and USA captain Bob Bryan. But it can also be a tricky situation that may ultimately require a little bit of luck to pan out the way you want it to be. And if it doesn’t work out, it puts the captain in the hot seat with the pressure to justify his or her selections.

In the competition’s current format, each team in Davis Cup is allowed a maximum of five players. In the knockout stage – the Final 8 – a tie consists of two singles matches and a doubles match, which is only played if the opposing teams split the two singles. Captains are required to submit their selections for the full slate of matches one hour before the start of a tie, not knowing, of course, who their opponents will be picking.

The first singles has to feature players that are ranked lower than the ones nominated for the second singles within each team.

On Thursday morning, Bob Bryan gave Ben Shelton his Davis Cup debut in the first singles, fielded his top player Taylor Fritz in the second singles, and initially selected experienced doubles pair Rajeev Ram and Austin Krajicek – silver medallists at the Paris 2024 Olympics – for the potential deciding doubles.

Hewitt went for Thanasi Kokkinakis in the first singles, Alex de Minaur in the second, and Matthew Ebden (Olympic doubles gold medallist) and Jordan Thompson (US Open doubles champion) for the doubles.

The first singles was an interesting choice from both captains with Shelton being the third-highest ranked singles player on his team – behind Fritz and Tommy Paul – and Kokkinakis being Australia’s fourth man behind De Minaur, Alexei Popyrin, and Thompson.

World No.77 Kokkinakis eked out a 6-1, 4-6, 7-6(16/14) victory over world No.21 Shelton to give Australia the opening point of the tie, saving four match points and needing seven of his own to close it.

Kokkinakis later said the Australians were under the assumption that Paul would have been his opponent in that match, not Shelton.

“I hadn't seen Ben the last two days. I saw Tommy earlier at breakfast, so I thought he was maybe going to play. He warmed up with Taylor earlier. It was a surprise to me,” Kokkinakis added.

Fritz, the world No. 4, levelled the tie for USA by defeating De Minaur for the second time in eight days (he also beat the Aussie at the ATP Finals last Thursday).

When Fritz spoke to reporters after the match, he was asked if there were any mind games that went into the decision to put Shelton and not Paul in the opening singles.

“I don't think we're really playing too many mind games. We thought Popyrin was going to play,” said Fritz, noting that Kokkinakis was not the obvious choice given he is ranked some 50 spots lower than Popyrin.

“But I think sometimes you can almost do the wrong thing if you get too deep into the mind games. Look, I see why they played Thanasi. He had some big wins for them in the last stage. Maybe he felt like he was playing the best in practice.

“You know, I just got here (from the ATP Finals in Turin). Everyone else was here before me. But from what I heard, everyone felt like Ben was playing really great in practice, so that's why we wanted to put Ben in.”

Fritz dismissed the idea that any mind games were involved that morning and believes it was all about match-ups. The American was one of the last to arrive to Malaga, having competed in the final in Turin on Sunday, and ideally would have been rested for Thursday’s clash against the Aussies.

“But if I don't play, then it's Tommy, and Tommy plays (in the No. 1 spot) and Ben plays second, and if Demon (De Minaur) is playing, which we found out he was, then Demon's record is very good on Tommy, so, okay, I should play this one,” he explained.

“There is more strategic stuff going on in terms of how you think you match up to who the other team is going to play.

“I think in today's situation, both teams just picked off of who they felt was playing well this week.”

Moments after Fritz finished his press conference, it was announced that USA made a last-minute change in nomination for the doubles, which is only permitted for the doubles after a tie is taken to 1-1. Instead of the obvious choice of doubles specialists Ram and Krajicek, who won silver together at the Paris Olympics, Bryan changed his lineup to pair Paul and Shelton together.

They ended up losing 6-4, 6-4 to Ebden and Thompson.

Bryan said they spent 15 minutes discussing the selection between the second singles and the doubles match before making the decision to partner Shelton with Paul.

The reason behind the last-minute switcheroo?

“Thompson, obviously US Open champion, finals of Wimbledon, a very accomplished doubles player. Matt Ebden won the Olympics. Matt Ebden has seen Rajeev and Austin play a bunch in the last couple of years, and he hasn't seen too much of Ben and Tommy,” said the USA captain.

“It was a tactical thing trying to take them by surprise. Ben was obviously on the court for three hours earlier in the day, so you find rhythm out there. Tommy, you saw what he did at the Olympics (winning bronze alongside Fritz in men’s doubles). We all respect his doubles. We took a shot at it.”

It was a particularly interesting choice given Bryan was a world No. 1 doubles specialist during his playing days and may have opted for a traditional doubles selection instead of going for two singles players.

“As a captain, you have to make tough decisions,” he said. “I had a lot of information behind the decision. We have been here for six days practicing. We know how everyone is feeling, and we know a lot about the opponents that we're playing. It's a world of analytics.

“This wasn't a black-and-white decision. It was razor-thin edge and we went with it. We knew it could have turned out like it did, because we're playing a tough team. But I don't regret anything about this.”

Bryan says he is “fortunate” to have so much talent to select from when it comes to the US Davis Cup team but “that makes my decisions a little bit tougher, because we are leaving some great guys at home. Frances Tiafoe made the semis of the Open, finals in Cincinnati. He's at home,” he stated.

“Unfortunately, there's not a lot of roster spots. There is only five. I brought the five guys that I thought would have the best chance to win this Davis Cup, and even after today's result, I wouldn't go back and change anything.”

In Hewitt’s case, his decision to pick Kokkinakis over Popyrin or Thompson in the opening singles paid off, and the Aussie captain said he had “full belief” in him going in.

Kokkinakis said he could make a case for any one of that trio to play in singles and he wouldn’t have been disheartened had he not been selected. But he also believed he could step up in this team format and deliver the victory.

“He was hitting it a treat all week leading in. He got what he deserved. He put a very tough training block in for us to get that win today, which was bloody important,” said Hewitt of Kokkinakis.

Hewitt said he was “not surprised” by USA’s change in doubles nomination and backed his own pair of Thompson and Ebden against any partnership.

Both Thompson and Ebden were competing in the ATP Finals doubles tournament last week in Turin but with different partners.

Thompson and Ebden took a few days to gel together in Malaga before delivering an important victory that has carried Australia into the Davis Cup semifinals.

Hewitt is a former world No. 1, who won the Davis Cup twice as a player, and has led Australia to the final in 2022 and 2023 as team captain.

In his playing days, the Davis Cup format was different and featured home and away ties played over three days, where teams were selected before the weekend of action began.

He openly dislikes the current format and says “it's not easy for everyone, to be honest”.

“There's a certain degree of strategy involved now, absolutely,” he added.

Spain captain David Ferrer had the daunting task earlier in the week of selecting his lineup for the hosts’ quarterfinal against the Netherlands. With Rafael Nadal announcing the Davis Cup would be the last tournament of his professional career, Ferrer selected the Spanish legend to play in the first singles over a player like Roberto Bautista Agut, who had far more match-play under his belt in comparison. Spain ended up losing 2-1 to the Dutch and were eliminated.

Ferrer stood by his decision to choose Nadal and dismissed the idea that it was a tough situation to manage.

“It wasn't difficult. In the end, I am the captain. I decide which players are going to play, and we knew that Holland, they have good players. And with this format never is easy,” said Ferrer.

There have been some bold and interesting decisions made on the Billie Jean King Cup side this fortnight in Malaga, many of which paid great dividends.

Tathiana Garbin captained her side to the title by making a key switch in singles from Elisabetta Cocciaretto, who lost her match in Italy’s quarterfinal win over Japan, to Lucia Bronzetti, who had never played a singles match in the BJK Cup before but won both her clashes, over Poland’s Magda Linette and Slovakia’s Viktoria Hruncakova, when she was called upon. Italy wouldn’t have won the Cup without her.

Japan’s Ena Shibahara, who is more experienced in doubles than singles, stepped up big time for Japan, taking the No. 1 singles spot in her side’s victory over Romania. Japan captain Ai Sugiyama had full faith in Shibahara, who went 2-0 in singles this week.

Team selection really is a delicate art and captains have to take so much into consideration before making a decision. Its highs and lows have been on full display in Malaga this week, and it will no doubt continue to spark plenty of debate moving forward.