The 6-3, 5-7, 7-6 (9/7) win took the Swede’s record this season to 10-1 while also securing a first career victory over the German after losing all three of their previous matches.
This was his first tournament after a disappointing showing at the Australian Open last month, where he was bounced out of the fourth round by an unheralded Ukrainian. Söderling will now face 2007 champion Mikhail Youzhny in a rerun of the 2010 final for a place in Saturday’s semi-finals.
Top-seed Söderling, the runner-up at the French Open in the last two seasons, was made to work by Kohlschreiber, having to come back from a break in the third set and saving a match point in the tiebreaker.
He finally claimed victory after 2 hours 22 minutes on his third match point after firing 16 aces to a dozen for the German.
Youzhny, the Russian sixth seed, eliminated the last Dutchman in the field, dispatching Thiemo de Bakker 6-4, 6-4 to improve to 13-5 lifetime at the tournament.
Söderling won the title in 2010 when Youzhny retired hurt trailing 0-2 in the second set.
Seventh seed Ivan Ljubičić rediscovered his winning form to bury a three-year winless drought at this tournament.
The veteran, who turns 32 in a month, advanced into his second consecutive quarter-final of the season with a 6-0, 6-4 win over French qualifier Benoît Paire.
For Ljubičić, regaining the winning formula this week has been a tonic after first-round defeats in the past three editions at the Ahoy stadium.
“It’s nice to be back in this way, I’ve lost my last four matches on this court. I’ve been coming to Rotterdam a long time but the last three years have
been difficult for me,” said Ljubičić, ranked 15th, who also saw off number 136 Paire in the Australian Open second round.
The losses were made all the more painful, coming in the wake of finals in 2005 and 2007 for the Croatian. The holder of 10 trophies also played a quarter-final last week at home in Zagreb, going out to eventual champion Ivan Dodig.
Fourth seed Tomáš Berdych, who had a one-hour stroll in the opening round, had to work for more than two hours Thursday to get past Russian qualifier Dmitry Tursunov 6-4, 4-6, 7-5.
“Conditions here suit my game, I served well and played aggressive,” said Berdych, who lost the Wimbledon final last year to Rafael Nadal after beating Roger Federer in the quarter-finals.
Berdych next faces eighth-seeded Frenchman Jo-Wilfried Tsonga for a semi-final spot.
Marcos Baghdatis, the conqueror of Andy Murray, won on his 10th ace, defeating Feliciano López of Spain 7-6 (7/3), 6-3.
“It was a tricky one,” said the Cypriot. “He gives you no rhythm, I had to find a solution to win.”