Novak Djokovic of Serbia celebrates after beating Alexandre Muller of France in their first round men's singles match at the Wimbledon Tennis Championships in London.

Novak Djokovic of Serbia, right, greets Alexandre Muller of France at the net after winning their first round men's singles match at the Wimbledon Tennis Championships in London.

Novak Djokovic of Serbia celebrates after beating Alexandre Muller of France in their first round men's singles match at the Wimbledon Tennis Championships in London.

Novak Djokovic of Serbia returns to Alexandre Muller of France during their first round men's singles match at the Wimbledon Tennis Championships in London.

Alexandre Muller of France returns to Novak Djokovic of Serbia during their first round men's singles match at the Wimbledon Tennis Championships in London.

Novak Djokovic of Serbia serves to Alexandre Muller of France during their first round men's singles match at the Wimbledon Tennis Championships in London.

Alexandre Muller of France stretches to return to Novak Djokovic of Serbia during their first round men's singles match at the Wimbledon Tennis Championships in London.

Supporters of Novak Djokovic of Serbia watch as he plays Alexandre Muller of France during their first round men's singles match at the Wimbledon Tennis Championships in London.

Novak Djokovic of Serbia returns to Alexandre Muller of France during their first round men's singles match at the Wimbledon Tennis Championships in London.

Alexandre Muller of France returns to Novak Djokovic of Serbia during their first round men's singles match at the Wimbledon Tennis Championships in London.