Wimbledon: Serena William's big gun puts the wind up Dominika Cibulkova

Dominika Cibulkova was exposed to the full fury of the Serena Williams serve for the first time on Saturday and the Slovak will not forget it in a hurry.

Thankfully the only bruises she sustained were to her pride as she scored just six points in an 18-minute first set rout before she rallied admirably to push the defending champion.

Members of the British military sat in the Royal Box on Armed Forces Day at Wimbledon and they must have been tempted to jump down and rescue a damsel in distress as the 5ft 3ins Cibulkova cowered under a ferocious barrage of thunderbolts.

She showed admirable fortitude under fire, however, and recovered her senses to make a match of it and walked off with her head held high after a 6-0 7-5 third-round defeat.

Hard-to-please Williams, who served 19 aces and leaked just six points on serve, said she needed to improve despite winning half of her sets so far 6-0.

There is clearly nothing wrong with her delivery though, just ask Cibulkova.

"She was serving like crazy," 21-year-old Cibulkova told Reuters. "It's the best serve I've ever faced, even though I played twice against Venus.

"I couldn't even hit the ball because it was so powerful and so far away from me on the lines."

Williams agreed.

"It feels good. Serving that well feels awesome," she told reporters. "I serve well at Wimbledon for some unknown reason. I wish I could serve like this every tournament.

"For the most part my serve works when I'm in trouble. At Wimbledon it works the whole match."

Williams cranked up the first serve to 120mph in the opening set as Cibulkova was totally overwhelmed. The second set was a scrappy affair as she appeared to lose her focus.

"It's almost better not to win 6-0 because then the crowd really gets behind the opponent. You can't blame them," added Williams who now faces a last-16 clash with Maria Sharapova in a repeat of the 2004 final that was won by the Russian.

"I kind of came off the gas a little too much today," she said. "You just can't do that in big grand slams like this."  

Against a resurgant Sharapova she is unlikely to let her guard drop for a second.

"You always have to be ready against her," Williams said. "She's obviously really good, especially on grass. I definitely have to pick up and play better."