Federer went through to the semi-finals despite a bad night's sleep

The world number one revealed he had bruised his shin after springing out of bed the night before his 4-6 7-5 7-6 (7-3) win over Japan's Takao Suzuki.

"I jumped out of bed and stood up screaming in a state of shock. I didn't know where I was," Federer said.

"I ran and hit the corner of the bed and I have a big bruise now. It was a pretty scary moment."

Federer's girlfriend Mirka calmed down the four-time Wimbledon champion but the pair had differing views on what could have sparked the nightmare.

"Mirka grabbed me and told me to relax," Federer explained. "She thinks I have been playing too much tennis this year and that is why it happened.

"But I think it might have been the sake bomber I had during dinner."

After the unsettling night, Federer had to battle hard to beat Suzuki, the world number 1078 in three sets.

Federer, playing his first event since retaining his US Open crown last month, admitted he had been lucky to come through the match.

"It was a difficult match and I was afraid I might lose it," he said. "I could see the headlines, 'Federer loses to a guy outside the top 1,000'. I'm glad I won, it saved my image.

"He mixed up his serves well and hit all the corners. I got a bit of luck here and there in the third set which helped."