Newly-crowned US Open champion Alexander Zverev makes a quick return to action this weekend as he bids to help Germany reach the Davis Cup Finals, while American Ben Shelton hopes to put his Flushing Meadows final defeat behind him.
World No 2 Zverev downed Shelton in four sets on Sunday to continue a dream season after ending his long wait to win a Grand Slam title at the French Open in June.
Leading Germany to a first Davis Cup crown since 1993 would cap off his year in style.
But to reach November's eight-team Finals, the Germans must first get through a second-round qualifying tie against Croatia in Halle on Saturday and Sunday.
The seven qualifiers will be decided this week, joining hosts and three-time defending champions Italy in Bologna in two months' time.
Zverev admitted that his coaching staff were not keen on him being back on court so quickly.
"I really, really would like to play in the Davis Cup. Everyone around me is trying to talk me out of it," he said after lifting the US Open trophy, which he initially did not realise he had won after match point.
Michael Kohlmann's Germany will be strong favourites to get the better of a Croatia team including 37-year-old Marin Cilic and youngster Dino Prizmic.
The Croatians have not reached the Finals since a group-stage exit in 2023, when there were still 16 teams taking part.
"Now the goal is to stand our ground against a strong opponent, together with the team and the fans," Zverev said last month.
"We want to experience a fantastic weekend of tennis together and qualify for the Finals once again."
Germany came up just short in the Finals last year, as Tim Puetz and Kevin Krawietz suffered only their second defeat in 24 Davis Cup matches together in a deciding doubles rubber against Spain in the semifinals.
US-CZECH SHOWDOWN
The United States, record 32-time winners of the competition, face a serious test in their bid to end a 19-year wait for a 33rd title when they take on a strong Czech Republic side in Prague on Friday and Saturday.
There will be even more pressure on Shelton to deliver after world number 10 Taylor Fritz and Tommy Paul both withdrew from the American team.
Rising star Learner Tien and world number 104 Martin Damm were named as their replacements. Damm shares his name with his Czech-born father, a 2006 US Open men's doubles champion.
French Open semifinalist Jakub Mensik, 24th-ranked Jiri Lehecka, Tomas Machac and Vit Kopriva make up the home outfit, captained by Tomas Berdych.
It will be a rematch of the second-round qualifying tie from last year, when Mensik beat Frances Tiafoe in a deciding singles rubber to give the Czechs a surprise 3-2 victory in Delray Beach.
USA skipper Bob Bryan, who was in the team the last time they won the trophy in 2007, will need Shelton at his best, despite the new world No 4 admitting he was "tired before I took the court" for the US Open final.
The winners of the contest between South Korea and India in Seoul will become the first Asian country to reach the quarterfinals since Kazakhstan in 2021.
The Koreans have included Kwon Soon-woo and Chung Hyeon, a former Australian Open semifinalist now ranked 549th in the world, in their team.
Rafael Jodar, who turns 20 on Thursday, will make his Davis Cup debut for Spain as they continue their tilt at a seventh title against Chile in Santiago.
"It's so exciting to be able to represent Spain for the first time," said the world number 14.
"I was a hitting partner two years ago in Valencia and it was an incredible experience. I can't imagine what it's like as a player."
Britain, featuring surprise Wimbledon semifinalist Arthur Fery, welcome Ecuador to London, while Austria take on Belgium, for whom Alexander Blockx withdrew following his run to the US Open quarters.
Felix Auger-Aliassime and Arthur Fils are slated to go head-to-head as Canada face France in Quebec City.