Top seed Andy Murray fended off an inspired Martin Klizan to reach the third round of the French Open on a hot Thursday in Paris.
The world number one recovered from an unconvincing start and also fought back from a break down in the fourth set to win 6-7 (3-7) 6-2 6-2 7-6 (7-3) in three hours and 34 minutes.
Murray was given a stern test by the unseeded Klizan, whose deft drop shots and ferocious forehands had the Brit scampering, but it was last year's runner-up who prevailed.
The three-time grand slam champion struggled on serve, but drew on his battling qualities and mixed his game up well on an energy-sapping day five to set up a meeting with Juan Martin Del Potro.
Murray made an uncertain start and was punished when he put a forehand wide to go a break down at 2-1 against an opponent who was involved in a tense first-round match, which resulted in Laurent Lokoli refusing to shake his hand.
The Slovakian left-hander was guilty of some poor decision making when serving for the set, though, getting two drop shots all wrong before dragging a backhand wide to be pegged back at 5-5.
Klizan - who went on to make 67 unforced errors - threw his racket down after Murray held in the next game, but regained his composure to hold and was a set up after winning a tie-break in which the Wimbledon champion was unhappy with a line call prior to double faulting.
The Scot took the upper hand in the second when Klizan netted a backhand to go 3-2 down and Murray broke again before somehow winning a point he had no right to with magnificent defence as he served out the set.
A fired-up Murray was transformed, racing around the court with vigour and raised the decibels with a sublime overhead backhand winner, going on to lead by lead two sets to one.
Klizan was not finished yet, his booming forehand and canny drop shots moving him into a 3-0 lead, yet Murray was in no mood to go the distance.
He broke back with a smash when Klizan served to level the match and fittingly sealed a tie-break win with a brilliant winner at full stretch to go through.
Murray  bt Klizan 6-7 (3-7) 6-2 6-2 7-6 (7-3)
Murray - 41/29
Klizan - 57/67
Murray - 9/4
Klizan - 5/7
BREAK POINTS WON
Murray - 6/14
Klizan - 2/7
FIRST SERVE PERCENTAGE
Murray - 50
Klizan - 55
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Murray - 79/62
Klizan - 63/54
Murray - 144
Klizan - 118