Stockholm - France's Gael Monfils stayed in the hunt for a place at the year-ending ATP World Tour Finals, coming from behind in the final set to defeat Bernard Tomic 6-4, 6-7 (4/7), 6-4 at the Stockholm Open on Thursday.
The top seed, and last man standing in the leading four at the Kungligahallen, trailed by a break in the third set before breaking the teenage Australian for 4-all.
He then sealed a 5-4 lead with his 18th ace, reaching the quarter-finals on his third match point.
Monfils is competing for the first time in a fortnight after a knee injury suffered in Bangkok.
He is one of the last possible contenders in the points race to reach the eight-man World Tour Finals in London from November 20, with a provisional place of 15th.
The flamboyant French player has three more tournaments this season, giving him chances to rise in the table.
"I hope to finish the year very strong," said the No 10.
"It was a tough battle tonight. He's a good young player, I needed time to adjust after time away. I had a big drop in the second set, but I'd been playing well until then.
"I need a few more matches before I can win in straight sets. I need to improve my concentration, but I did a pretty good job today."
Monfils will play South African sixth seed Kevin Anderson for a place in the semi-finals.
Two-time finalist Jarkko Nieminen of Finland eased past third seed Stanislas Wawrinka 6-3, 6-4.
The exit of the Swiss in 71 minutes followed the defeat of fourth seed Juan Ignacio Chela, who was beaten by Bulgarian youngster Grigor Dimitrov 6-2, 5-7, 6-1.
No 2 Argentine, Juan Martin Del Potro, was beaten on Wednesday in his opening match by James Blake of America.
Wawrinka, ranked 19th, suffered another year of bad luck in the Swedish capital after losing a year ago in the quarter-finals to compatriot Roger Federer.
He smashed a racquet near the end of his ordeal against Nieminen, a finalist in 2001 and 2006 and playing the event for the 12th consecutive year.
The 73rd-ranked Finn will be competing in his second quarter-final in a month after reaching the last eight in Bangkok when he will face German Tobias Kamke, who beat Sebastian Rieschick 6-3, 6-1.
Nieminen took victory with 22 winners and a dozen unforced errors, breaking Wawrinka three times. The Swiss fired 24 winners but committed 21 errors.
Dimitrov, a 20-year-old tipped for a top career, admitted to a lapse against Chela after leading a set and 2-0.
"I started struggling a bit and he raised his game," said the 70th-ranked Bulgarian.
Dimitrov will next face Canadian sixth seed Milos Raonic.
"It will be a great match, I know him well and will have to be on my game."
Results on the third day of the Stockholm Open Thursday (x denotes seeding):
Gael Monfils (FRA x1) bt Bernard Tomic (AUS) 6-4, 6-7 (4/7), 6-4
Tobias Kamke (GER) bt Sebastian Rieschick (GER) 6-3, 6-1
Grigor Dimitrov (BUL) bt Juan Ignacio Chela (ARG x4) 6-2, 5-7, 6-1
Jarkko Nieminen (FIN) bt Stanislas Wawrinka (SWI x3) 6-3, 6-4
David Nalbandian (ARG) bt Ivan Dodig (CRO x7) 6-1, 6-1