Novak Djokovic wrapped up a Davis Cup quarter-final place for Serbia on Friday, beating Spain's Alejandro Davidovich Fokina just five days after winning the US Open title.
The world number one eased to a 6-3, 6-4 success to give his country an unassailable 2-0 lead in Valencia after Laslo Djere's earlier 6-4, 6-4 win over Albert Ramos-Vinolas.
It was Djokovic's first appearance in the team competition since Serbia's semi-final loss to Croatia in 2021.
The 36-year-old won a record-equalling 24th Grand Slam title last weekend with a straight-sets triumph against Daniil Medvedev in the US Open final.
"I'm on cloud nine with everything that has happened recently on the tennis court," Djokovic said.
"Playing for Serbia, for my country, is something completely different.
"It's a huge responsibility and pressure, but it's also a privilege and an honour."
Djokovic took the opening set against world number 25 Davidovich Fokina with a single break in the eighth game, before battling back from 4-1 down in the second set with a run of five straight games.
Serbia have now secured a spot in the knock-out phase which will be played in Malaga in November, after also seeing off South Korea 3-0 on Tuesday, while Spain are out of the competition.
"It can create some pressure," said Djere on having Djokovic back in the team.
"But I try not to put any pressure on myself and use it as motivation. I think I managed quite good in doing so."
Djokovic played a starring role when Serbia won their only previous Davis Cup title in 2010.
Serbia wrapped up a 3-0 victory in the Group C tie as Nikola Cacic and Miomir Kecmanovic beat Davidovich Fokina and Marcel Granollers 6-4, 7-6 (15/13).
They will round off their group campaign against the Czech Republic on Saturday.