STOCKHOLM (AP)—Finland’s Jarkko Nieminen swept past a below-par Tomas Berdych 6-1, 6-4 Wednesday to make it through to the quarterfinals of the Stockholm Open.

No. 6 Berdych lost seven consecutive games at one point against a player ranked 39 places lower, and whom he had beaten in four previous encounters.

Backed by a supportive crowd at the Royal Tennis Hall, Nieminen got off to a fast start and broke third-seeded Berdych twice to take the first set.

Nieminen then took a 2-0 lead at the start of the second, and played some inspired tennis, including a laser-guided backhand pass in the fifth game that Czech-born Berdych could only watch.

Fifth-seeded Stanislas Wawrinka also advanced, the Swiss hitting 12 aces on the way to beating Robin Haase of the Netherlands in a marathon 2 1/2 -hour three-setter 7-5, 6-7 (6), 6-4.

Wawrinka recovered from a shaky start, coming back to break Haase twice in the last three games of the first set. Both players held serve in the second, with Haase eventually prevailing after a closely fought tie-break.

It was a mixed match for Wawrinka. He ripped some fine backhand and forehand winners, but also overhit some shots when Haase looked beaten.

“It was a really tough match for me today,” Wawrinka said. “I had four match points I think in the second set, but I just tried to stay focussed on my game and concentrate for the third set.”

In the quarterfinals, Wawrinka will meet the winner of Thursday’s match between compatriot Roger Federer and the American Taylor Dent.

In the remaining first round matches, Matthias Bachinger of Germany beat Poland’s Lukasz Kubot in three sets 6-4, 4-6, 6-3, and countryman Tobias Kamke defeated Jan Hajek of the Czech Republic 6-0, 6-2.

Florian Mayer of Germany beat Sweden’s Michael Ryderstedt in straight sets 6-4, 6-4 on center court in the last match of the day.