Novak Djokovic has described his third-round meeting with Roberto Bautista Agut at the French Open as a "great test" for him.
The Serb edged the contest 6-4 6-7 7-6 6-2, having been taken to two tie-breaks during the gruelling four-hour match.
"It was a great test. I had to earn my victory," BBC Sport quotes Djokovic as saying at Roland Garros.
"The last set was actually the best set that I have played so far in the tournament. I don't feel too exhausted. That's the good news."
The 12-time Grand Slam winner will take on Fernando Verdasco in the last 16 of the competition.