Defending champion Robin Soderling came within a point of losing to Germany's Philipp Kohlschreiber at the World Indoor tournament on Thursday before sealing a quarter-final spot with a 6-3, 5-7, 7-6 victory.
The top-seeded Swede needed two hours and 22 minutes to finally subdue the tricky Kohlschreiber and join powerful Czech Tomas Berdych in the last eight of the indoor event.
Berdych, last year's Wimbledon runner-up, edged past Russia's Dmitry Tursunov 6-4, 4-6, 7-5 to set up a meeting with Frenchman Jo-Wilfried Tsonga.
The experienced Tursunov grabbed his one break point chance of the match to extend the contest into a deciding set and Berdych was relieved to scrape through.
"It was a close match between two players who play their best tennis on this surface and today I was the luckiest one," fourth seed Berdych told reporters.
"Now I will have my first match against (Jo-Wilfried) Tsonga on the tour and I am happy about that but it won't be easy."
Soderling saved a match point at 6-7 down in the third set tiebreak against Kohlschreiber before sealing victory, his first against the German, when his opponent netted a forehand.
The world number four will now face Mikhail Youzhny who he beat to win the title 12 months ago when the Russian retired during the match with an injury.
"It was very close today but as far as I know our matches have always been close," Soderling, who had lost his three previous matches with Kohlschreiber, told reporters.
"This is my first win over him and also the first tiebreak I won against him and that feels comfortable as he is a very tough opponent with a varied game."
Cypriot Marcos Baghdatis also reached the last eight as he followed his impressive win over Andy Murray on Wednesday with a 7-6, 6-3 win over Feliciano Lopez of Spain.
Baghdatis now plays Croatian Ivan Ljubicic who continued his good form at a tournament in which he was finalist in 2005 and 2007/ He brushed aside French qualifier Benoit Paire 6-0 6-4.