Justine's best on grass is....maybe against Kim in the Wimbledon '06 semis?
Not even close. Justine played better matches against Capriati in the 2001 Wimbledon semis, Serena in the 2007 Wimbledon quarters, Kuznetsova in the 2003 Wimbledon quarters, Seles in the 2002 Wimbledon quarters.
Anyway Justine's worst surface is not grass, but fast U.S Open style decoturf. I know that sounds funny when she has 2 U.S Open titles, another final, and a dominant Indian Wells win in 2004, but she also has a whopping 5 round of 16 defeats at the U.S Open. Contrast that to rebound ace, grass, carpet, medium hard courts, where she is always making late rouns. Despite that she is still far better than Kuznetsova on it or any other surface, contrary to what AcesHigh believes.
Venus's best match on clay was the 1999 Hamburg final vs Mary Pierce which she won 6-3, 6-0. A close 2nd would be beating Justine Henin on clay at Charleston in 2002 after being down 6-2, 4-0.
Serena's best match on clay would be the 2002 Rome final where she beat Justine Henin in straight sets.
Sharapova's best match on clay would actually probably be the Rome final where she crushed Stosur.
Clijster's best match on grass would be her Wimbledon round of 16 win over Henin at Wimbledon 2010, her only ever decent win on grass.
Davenport's best match on clay would be crushing Mary Pierce in the 1997 Charleston final.
Hingis's best match on grass would be her 3 set win over an injured Novotna in the 1997 Wimbledon final.
Kuznetsova's best match on grass would be the 2007 Wimbledon quarters where she got 7 games off of Venus Williams.
Wozniacki's best ever match on hard courts would either be the 2010 WTA Championships final where she lost to an erratic and off form Kim in 3 sets, or the 2010 Indian Wells final where she managed to win a set then win 4 games in the last 2 sets vs a sluggish and past her prime Henin.
Kvitova's best ever match on outdoor hard courts would be her performance vs Kirilenko at the 2011 Australian Open. For a full match her straight sets win over Stosur at the 2011 Australian Open, where Sam actually played very well and just got outplayed, or her straight sets win over a pretty good Ivanovic at this years Australian Open. Maybe even her 3 set loss to Sharapova at this years Australian where she played well for most of the match despite her usual errors binge, and played in god mode during the 2nd set.
Mauresmo's best ever match on fast U.S Open style decoturf (her worst surface, like Justine) was her 3 set win over Clijsters at the 2002 U.S Open. Her 3 set win over her pigeon Capriati only came due to a big choke from Capriati when serving for it in 2 sets, she played crap most of that match in fact. She played pretty well in her 3 set loss to an off form Venus in the semis, and got screwed on some major line calls that might have cost her the match.