It took a comeback, a vintage performance and a lot of fist pumps, but Roger Federer has managed to preserve his record streak of 36 straight Grand Slam quarterfinals. The narrow margin by which he won his fourth-round match against Gilles Simon on Sunday in five sets reinforced just how remarkable Federer's run has been.

The Simon match was the ninth in which Federer played a winner-take-all fifth set before the quarterfinal of a major since the streak began almost nine years ago, at Wimbledon in 2004. It was the sixth time...