By Mark Meadows
Whether it was Sharapova's yellow dress or the bright Roland Garros sun, German 15th seed Andrea Petkovic was left dazed and dazzled in a 6-0 6-3 defeat while Li had more of a tussle in a 7-5 6-2 win over Belarus fourth seed Victoria Azarenka.
"I don't remember the last time we played but I'm very excited to be in the semi-finals," Sharapova said courtside when asked about her 2009 last-16 win over Li on the Paris clay.
The clinical performances whetted the appetite of fans on the two main courts for the remaining men's quarter-finals.
Holder Rafa Nadal plays Robin Soderling, the only man to have beaten him at Roland Garros, in a repeat of last year's final while British battler Andy Murray takes on the only unseeded player left in either draw -- Juan Ignacio Chela.
Racing through the first set without any need for extravagance, Sharapova looked almost as shocked as her opponent but the second was more of a duel with the Russian's grunting contrasting markedly with her poise around court.
The former world number one sealed her progression when Petkovic netted a routine forehand on her own serve.
A slow start to the second grand slam of the season became a shrewd bid at peaking at the right time for the seventh seed once the top three seeds crashed out early.
Dogged defending champion Francesca Schiavone or French crowd favorite Marion Bartoli await in Saturday's final but Sharapova must first negotiate a passage past fighter Li.
The first Chinese to make it this far at Roland Garros never gives up on any point and January's Australian Open runner-up also has the backing of millions of fans back home.
The sixth seed charged back from going a break down at 2-1 by hitting every shot with all her might so that Azarenka
The sixth seed charged back from going a break down at 2-1 by hitting every shot with all her might so that Azarenka , a hot tip after her good form in the buildup events, just could not dictate any game. Li repeated the same trick in the second set before surging to victory. "This is a huge surprise for me," Li said. (Editing by Tony Jimenez)