Wimbledon: Day 4

Ana Ivanovic returns to Eleni Daniilidou of Greece during their second-round match.

Serena Williams prepares to serve during her second-round match with Romania's Simona Halep.

Simona Halep serves to Serena Williams during their second-round match.

Serena Williams returns to Simona Halep during Thursday's match.

Slovakia's Dominika Cibulkova in action during her second-round match against Slovenia's Polona Hercog.

Christina McHale, a 19-year-old from Englewood Cliffs, N.J., returns a shot against Austria's Tamira Paszek.

Covers are pulled over a court as rain stops play at Wimbledon.

Serbia's Novak Djokovic returns a shot to South Africa's Kevin Anderson during their second-round match.

Russia's Maria Kirilenko in action during her second-round match against Thailand's Tamarine Tanasugarn.

Australia's Lleyton Hewitt reacts during his second-round match against fifth-seeded Robin Soderling.

Robin Soderling returns to Lleyton Hewitt during Thursday's match.

Fans wacth Great Britain's Andy Murray warming up on the practice courts.

A security guard is seen with a dog on Court 1 at the All England Club.

Roger Federer leaps to make a forehand return to France's Adrian Mannarino during their second-round match.

France's Jo-Wilfried Tsonga falls to the ground during his second-round match against Bulgaria's Grigor Dimitrov.

Germany's Sabine Lisicki reacts after defeating China's Li Na on Centre Court.