World number one Rafael Nadal showed his trademark grit and determination on Thursday as he reached the semi-finals of the ATP Tour’s Qatar Open with a 7-5 6-4 victory over Latvian Ernests Gulbis.

He will now meet qualifier Peter Gojowczyk who overcame the flamboyant, dreadlocked Dustin Brown 7-5 in the third set tie-breaker during an all-German quarter-final on centre court.

Nadal, who needed three sets to overcome German Tobias Kamke to reach the last eight, took the opening set 7-5 before going down a break and trailing 3-0 in the second set against the 1.90m Riga native.

“This is a tournament I really like to play and I’ve won here before and reached the final so I’m really happy,” he said.

“I’m just thinking about Doha at the moment and not looking ahead to the Australian Open (the year’s first Grand Slam which starts later in January).”

He now faces Gojowczyk, who took the first set 6-3 against Brown before the 111th-ranked right-hander levelled the match by the same scoreline to send it to a final set decider.

Romania’s Victor Hanescu was due to meet Florian Mayer of Germany before Frenchman Gael Monfils took on Germany’s Daniel Brands in the remaining quarter-finals.