Andy Murray survived a stern examination of his aspiration to be world No 1 from Fernando Verdasco to reach the third round of the BNP Paribas Masters.
British No 1 Murray needs to at least reach the final in Paris to stand a chance of overhauling Novak Djokovic on Monday and becoming the first British player to be ranked No 1 in singles.
That looked highly unlikely when a weary Murray faced two break points at 5-5 in the deciding set against an inspired opponent, but the Scot held on and ground out a 6-3 6-7 (5/7) 7-5 victory.
It was a 16th win in a row for the 29-year-old, who is bidding for a fourth straight title after winning trophies in Beijing, Shanghai and then Vienna last week.
The first set was plain sailing, but Verdasco, whose forehand can be one of the biggest weapons in the game, stepped things up impressively in the second.
He broke Murray for the first time in the fourth game with a crisp winner and then, after the second seed had pegged him back, moved ahead again for 5-3.
Verdasco failed to serve it out, but was not to be denied in the tie-break, taking a 6-2 lead and finally converting on his fourth set point when Murray netted a backhand.
Murray looked to have made a key breakthrough when he opened up a 2-0 lead in the decider, but back came Verdasco.
Murray was beginning to look tired and was on the back foot for much of the third set.
The crunch moment came when Verdasco moved to 15-40 at 5-5, but he could not convert either chance, being denied by a net cord on the second.
The Spaniard, who has a reputation for faltering at the last, then played a dreadful game to hand Murray the victory.
The Wimbledon champion next faces 13th-seeded Frenchman Lucas Pouille today.