5 things to look for at Wimbledon

London: Roger Federer's nearly perfect serving carried him back to the Wimbledon quarterfinals.

   
He'll try to continue his bid for a record eighth championship at the All England Club by beating his friend and countryman Stan Wawrinka on Wednesday.
   
Federer won all 54 service games through his first four matches in the tournament, saving eight break points.
   
That included saving the only break point he faced in a 6-1, 6-4, 6-4 victory over No. 23 Tommy Robredo in the fourth round Tuesday. In the second set, Federer won all 20 points he served.

"Now I'm confident again and not fighting with any confidence issues, which is huge in sporting terms," said Federer, who lost in the second round at Wimbledon a year ago. "I'm happy I got through the first rounds here rather comfortably."
   
Here are five other things to look for at Wimbledon.