Paris - Juan Martin del Potro edged past Tomas Berdych in a battle of big-hitting baseliners to book his spot in the French Open quarter-finals, winning 7-6 (8/6), 1-6, 6-3, 7-5 on Monday.
After the match was suspended at the end of the third set due to bad light on Sunday evening, the ninth-seeded Argentine returned to wrap up victory in three hours 26 minutes.
"I got up (feeling) very positive and I restarted the match very focused and broke his serve, then he played better," Del Potro told reporters.
"But in the end, I was really focused on winning the fourth set, and I did it in the last game, playing really well."
Del Potro exchanged clubbing flat forehands with his opponent in a first-set struggle that lasted over an hour before Berdych struck back emphatically in the second.
The Argentine, who will next play Swiss third seed Roger Federer, returned to the ascendancy in Sunday's evening gloom before breaking decisively in the 12th game of the fourth set.
"I will walk on to the court with a very aggressive mindset; I want to play more volleys," Del Potro said about his quarter-final match against Federer.