Serbia carved out a 2-0 lead over rivals Croatia while Britain led the US by the same score and holders Switzerland were tied with Belgium in the Davis Cup world group first round on Friday.
Roared on by a passionate 3,000 crowd, who also applauded Croatia's national anthem, world number one Novak Djokovic put 2010 winners Serbia ahead with a 6-3, 6-2, 6-4 whitewash of Mate Delic before Viktor Troicki staged a magnificent comeback to beat 18-year-old Borna Coric in five sets in the Kraljevo Arena.
Trailing by two sets and 2-0 in the third, Troicki looked a different player after winning the next five games to haul himself back into the match.
The 29-year-old from Belgrade piled on the pressure against a worn-down Coric who looked completely deflated for the rest of the match and acknowledged he ran out of steam and energy after suffering a 4-6, 1-6, 6-3, 6-2, 6-1 defeat.
“I played an almost perfect match up to the point when I was two games up in the third set and, having missed some volleys which I shouldn’t have, I completely lost it,” said Coric, recently touted by Djokovic as the next big thing in men’s tennis after wins over Rafael Nadal and Andy Murray.
“Clearly, I lack the experience and stamina for five-set matches but that’s exactly where I will improve in the future.”
Troicki said: “I had to dig deep but I never lost faith and felt good on the court even when I was losing.
“The crowd really gave me a lift and they deserve a lot of credit for my comeback against a top quality player who has a very bright future.”
Britain's Murray cruised to a predictably comfortable 6-1, 6-1, 4-6, 6-2 win over Donald Young before James Ward, ranked 111th in the world, staged a comeback as impressive as Troicki’s to beat John Isner in five sets.
The 28-year old Londoner prevailed 6-7(4), 5-7, 6-3, 7-6(3), 15-13, clinching a marathon fifth set after conjuring triple match points in the final game of the contest which lasted four hours and 56 minutes.
Switzerland, missing their top two players Roger Federer and Stanislas Wawrinka, led Belgium after Henri Laaksonen recovered from two sets down to beat Ruben Bemelmans before Steve Darcis levelled the tie with a straight sets win over Michael Lammer.
Canada went up 1-0 on Japan as Milos Raonic beat Tatsuma Ito 6-2, 6-1, 6-2 in Vancouver. Backed by a partisan crowd, Raonic broke Ito twice in the first set, and cruised to victory with 17 aces to just two by his opponent.
Brazil was tied 1-1 with Argentina in Buenos Aires. The visitors struck first as Joao Souza topped Carlos Berlocq 6-4, 3-6, 5-7, 6-3, 6-2 in a five-hour marathon.
Argentina evened it up with Leonardo Mayer's win over Thomaz Bellucci 6-4, 6-3, 1-6, 6-3.
Kazakhstan shared the spoils with visitors Italy while Australia were 2-0 ahead against hosts the Czech Republic.
The Czechs, missing Tomas Berdych and Radek Stepanek, suffered an early setback when Australia’s Thanasi Kokkinakis fought back from a two-set deficit to beat Lukas Rosol before Bernard Tomic beat Jiri Vesely in straight sets.
France also raced into a 2-0 lead away to Germany after Gilles Simon overpowered Jan-Lennard Struff in five sets and Gael Monfils beat Philipp Kohlschreiber 6-4, 7-5, 7-6(4).
