(CNN) -- Stanislas Wawrinka has had little time to rest on his laurels after winning his first grand slam title but the new Australian Open champion rounded off a superb day for Switzerland as they took a commanding 2-0 lead over Serbia in a Davis Cup tie in Novi Sad Friday.
Wawrinka battled jet leg after the long haul flight from Melbourne -- where he had beaten Rafael Nadal in Sunday's final -- to see off Dusan Lajovic 6-4 4-6 6-1 7-6.
Earlier, former world number one Roger Federer, a late inclusion in a strong Swiss line-up, beat Ilija Bozoljac 6-4 7-5 6-2 to give them the advantage.
Serbia, beaten in last year's final by the Czech Republic, is fielding a much-weakened team with both world number two Novak Djokovic and Janko Tipsarevic sitting out the World Group match.
Federer came back from 5-2 down in the second set to snuff out any hopes Bozoljac might case an upset and he raced through the third set
"In the second set I was just glad to take advantage and fight back. The most important thing is that I won the match in straight sets," Federer told the official Davis Cup website.
Wawrinka took the first set against world number 102 Lajovic, but was in trouble in the second as the Serbian leveled.
The new Swiss number one raced through the third set, but the fourth was again a struggle and he needed unforced errors from the inexperienced Lajovic in the tiebreak to close out the match.
"It was a tough match and it wasn't easy for me to come here after the last few weeks," Wawrinka said.
"I didn't really have enough time to get ready as I was exhausted both mentally and physically, but I was determined to fight and win the match and I was really happy to get through it."
Nadal, troubled by a back injury during his four-set loss to Wawrinka, is missing Spain's tie against Germany and in his absence they have fallen 2-0 behind in Frankfurt.
Philipp Kohlschreiber was in superb form as he thrashed Spain's new boy Roberto Bautista Agut 6-2 6-4 6-2 while Florian Mayer came out on top in a marathon battle against Feliciano Lopez to win 7-6 7-6 1-6 5-7 6-3 in just under four hours.
Boris Becker, now in Djokovic's coaching team, was delighted to see his country performing so well against the five-time champions.
"And we have 2points against #spain in #frankfurt #DavisCup !!!!" he tweeted.
Holders the Czech Republic were involved in a tough battle with the Netherlands with Robin Haase beating Radek Stepanek 3-6 6-4 6-7 6-2 6-1 to put the Dutch ahead.
Tomas Berdych leveled for the Czechs with an easy victory over Igor Sijsling, 6-3 6-3 6-0.
On the WTA Tour, top seed Maria Sharapova reached the semifinals of the Paris Indoor Open with a 6-2 6-2 win over Kirsten Flipkens of Belgium, who had beaten titleholder Mona Barthel of Germany in the first round.
Sharapova will face fellow Russian Anastasia Pavlyuchenkova for a place in the final as she continues her comeback from an injury which wrecked the second half of her 2013 season.
Pavlyuchenkova beat ninth-ranked German Angelique Kerber, a Paris winner in 2012, in three sets in their quarterfinal tie.