Rafael Nadal rebounded after a five-week break from the ATP circuit when overcoming Raemon Sluiter 6-4, 6-2, to make a winning debut at the Stockholm Open on Tuesday.
Spain's world No. 2, with five titles in 2006, has ground to make up in his duel with Roger Federer after the Swiss won his ninth trophy of the season in Tokyo over Tim Henman at the weekend.
Nadal, whose last Tour match was a quarter-final U.S. Open loss to Mikhail Youzhny, won two Davis Cup matches over Italy last month in a brief return to action.
The 90th-ranked Sluiter was the second Dutchman to fall in the first round after popular Swedish veteran Jonas Bjorkman put out Peter Wessels 7-5, 6-2.
Nadal, who won an indoor title last year in Madrid, needed a set to get comfortable as Sluiter challenged throughout the opener before the top seed claimed the early lead.
The double Roland Garros winner broke to start the second set and tightened his grip on the match on the way to the second round.
Belgium's Kristof Vliegen blew out Nicolas Massu's hopes of a winning birthday celebration with a 6-2, 6-4 first-round win over the Chilean.
The seventh-seeded Vliegen broke five times in his one-hour, 20 minute win at the Kungligahallen.
The 24-year-old winner improved to 28-20 on the season, with the 27 victories more than he had amassed in his entire ATP career prior to 2006.
Massu turned 27 in depressing circumstances as he plowed a backhand into the net to lose on second match point.
"It's been almost 10 years that I haven't had a birthday at home which is always a bit sad," said Massu. "The last time was maybe when I was 17.
"But I'll go out this evening and have a nice dinner with my coach and some friends from Chile and have a good time.
"Unfortunately I wasn't able to give myself a birthday present today with a win."
Spain's Feliciano Lopez advanced when Argentine Juan Monaco pulled out with a right knee injury after 25 minutes.
Lopez next faces fourth-seeded compatriot David Ferrer in the second round, with the seed needing to win if he is to make up ground from his provisional 12th in the race for a possible place in next month's masters Cup in Shanghai.
Andreas Vinciguerra joined Bjorkman as a home winner, beating Nicolas Devilder of France 6-4, 6-1 while Frenchman Marc Gicquel defeated Briton Jonathan Marray 6-4, 7-6 (7/3).