Andy Murray was pushed to the limit by David Nalbandian before booking his place in the third round of the Rome Masters.
The former Wimbledon runner-up bounced back from a nightmare start to push Murray hard in the decider but the British number one, celebrating his 25th birthday, eventually prevailed 6-1 4-6 7-5 win.
There was no hint of the drama to follow when Murray, returning to action after missing last week's event in Madrid with a back injury, swept through the first set and looked ready for a quick night.
But Nalbandian battled back to level the match and went a break up in the decider before his frequent unforced errors began to tell and Murray clawed back to serve out for the match after two hours and 37 minutes.
There were no signs in the first set of Murray's stuttering start to the claycourt season, which apart from his back injury also saw him suffer a shock loss to Milos Raonic in the Barcelona Open last month.
Murray broke Nalbandian twice to blaze into a 4-0 lead and after breaking the Argentinian for a third time the Scot served out to take the set, with Nalbandian complaining about glare from the setting sun.
Nalbandian looked much stronger from the start of the second set, and both players found their form on serve with no break points for either until Murray served to stay in the set at 4-5 down and was broken.
Murray had the first chance in the decider, fashioning two break points on the Nalbandian serve at 1-1, but the Argentinian hung on and went on to break Murray to seize the advantage.
But Murray responded by breaking back immediately and grabbed the crucial second break at 5-5, when after spurning his first two of three break points, he only converted the third after the most fortunate of net cords.
Nalbandian was not quite finished, going 15-40 up on his opponent's serve as Murray served for the match, but a backhand drive which clipped the outside of the line helped Murray haul back to deuce before rounding off a gutsy win.
Murray will now face either 16th seed Richard Gasquet or local wild card Paolo Lorenzi in the last 16 on Thursday.
