Russian Maria Sharapova failed to advance to the third round of Wimbledon for the second year in a row on Wednesday. Russian Maria Sharapova failed to advance to the third round of Wimbledon for the second year in a row on Wednesday. (Owen Humphreys/Associated Press)

The Wimbledon tennis championship saw its first major upset unfold as former champion Maria Sharapova was upended by Argentina's Gisela Dulko in three sets on Wednesday.

Sharapova, the 2004 champion, was ousted after losing 6-2, 3-6, 6-4 in the second round at the All England Club.

Competing in only her fourth tournament since battling back from shoulder surgery last October, Sharapova was knocked out of Wimbledon's second round in consecutive years.

"This is not an overnight process," said Sharapova. "It's going to take time, as much time as I need on the court, to get everything together.… Just being here is a wonderful accomplishment."

The Russian, seeded 24th, struggled early with her forehand against Dulko. The Argentine also beat Sharapova with repeated drop shots.

After dropping the first set, Sharapova rallied from a 3-0 deficit to take the second. Sharapova unravelled in the final set, serving up double faults in two games to fall behind 4-3.

Dulko then put the match away when Sharapova sent a forehand long.

Serena Williams advances

"I had so many easy balls, and I just made unforced errors from those," said Sharapova. "When I've had those situations before, those balls would be pieces of cake, and today they weren't."

Sharapova had owned Dulko in the previous two matches, losing only three games in four sets.

American Serena Williams cruised into the third round, disposing of Australian Jarmila Groth 6-2, 6-1.

The two-time Wimbledon champion quickly showed her dominance before eliminating Groth in 58 minutes.

Williams, the third seed in the tournament, committed only six unforced errors in the match.

In the men's bracket, five-time Wimbledon champion Roger Federer breezed through his second-round match with Spaniard Guillermo Garcia-Lopez.

Federer overpowered Garcia-Lopez with superior shot-making and advanced to the third round with an easy 6-2, 6-2, 6-4 victory.

Never lost serve

The Swiss great registered 27 errors and committed only 10 unforced errors while never losing serve.

Another championship would secure Federer's 15th Grand Slam title, which would break a record he holds with American Hall of Famer Pete Sampras.

Federer is also in search of his sixth Wimbledon title in the last seven years.

He became the top seed in the tournament after No. 1 Rafael Nadal of Spain pulled out prior to the tournament because of knee problems.

Serbian Novak Djokovic used little effort getting into the third round, defeating German Simon Greul in straight sets.

The fourth seed won eight consecutive games early in the second set en route to a 7-5, 6-1, 6-4 win.

Djokovic exchanged breaks twice with Greul in the third, but took the lead for good in the ninth game.

Also Wednesday, it was:

  • Fernando Verdasco (7), Spain, over Kristof Vliegen, Belgium, 7-6 (3), 6-7 (3), 7-6 (4), 6-4.
  • Jo-Wilfried Tsonga (9), France, over Simone Bolelli, Italy, walkover.
  • Marin Cilic (11), Croatia, over Sam Querrey, U.S., 4-6, 7-6 (3), 6-3, 6-7 (4), 6-4.
  • Robin Soderling (13), Sweden, over Marcel Granollers, Spain, 4-6, 7-6 (7), 6-4, 7-5.
  • Tommy Robredo (15), Spain, over Stefan Koubek, Austria, 3-6, 4-6, 6-4, 7-6 (5), 6-1.
  • Dudi Sela, Israel, over Rainer Schuettler (18), Germany, 7-6 (3), 6-3, 6-2.
  • Ivo Karlovic (22), Croatia, over Steve Darcis, Belgium, 7-5, 6-3, 6-4.
  • Tommy Haas (24), Germany, over Michael Llodra, France, 4-3, retired.
  • Philipp Kohlschreiber (27), Germany, over Ivo Minar, Czech Republic, 6-4, 3-6, 4-6, 6-2, 8-6.
  • Mardy Fish (28), U.S., over Janko Tipsarevic, Serbia, 6-4, 3-6, 6-1, 6-4.
  • Igor Andreev (29), Russia, over Vince Spadea, U.S., 6-3, 7-5, 6-2.
  • Albert Montanes (32), Spain, over Guillermo Canas, Argentina, 6-4, 6-3, 4-6, 6-3.
  • Nicolas Almagro, Spain, over Karol Beck, Slovakia, 6-4, 7-6 (2), 3-6, 3-6, 7-5.
  • Andreas Seppi, Italy, leads Marc Gicquel, France, 7-5, 6-4, 6-7 (3), 5-5, suspended due to darkness.
With files from The Associated Press