Juan Martin Del Potro beat Roger Federer in a three-set thriller on Thursday to scrape into the ATP World Tour Finals semis with Federer by the tightest of margins.
The Argentine beat the Swiss world number one 6-2, 6-7 (5/7), 6-3 in two hours and six minutes at London's O2 Arena, and only just earned himself a spot in the last four at the agonising expense of Britain's Andy Murray.
Federer won the group, but with Del Potro and Murray both having won five sets to four in their three Group A matches, it went down to their games record. The Argentine went through to the semi-finals by a margin of one, his 45 games won to 43 lost record bettering the 44-43 of Murray.
Throughout the match, ATP statisticians were furiously calculating who was going through to the semi-finals.
“It's an incredible moment, my first Masters semi-final, I've nothing to lose,” said Del Potro.
Though Federer went into the match with a 6-1 overall lead on Del Potro, the Argentine pulled off a second decisive victory over Federer this season, having beaten him in the US Open final in their last clash.
Del Potro was supported by his friend Carlos Tevez, the Argentina and Manchester City footballer.
{{/usCountry}}Del Potro was supported by his friend Carlos Tevez, the Argentina and Manchester City footballer.
{{/usCountry}}Del Potro won the first game of the final set to love, then Federer held serve with some cunning soft shots.
Federer won the sixth game to love, meaning that at 3-3 with the Swiss mathematically through to the semi-finals whatever the result, Del Potro would be out if he lost a game.