Serena Williams survives scare to reach Wimbledon semi-finals

 Serena Williams clubbed her way into the Wimbledon semi-finals, draining the last drop of fight from fellow American Alison Riske before sealing a 6-4, 4-6, 6-3 win in a rip-roaring Centre Court contest on Tuesday. 

For two sets, Riske absorbed every last punishing blow from the seven times champion, while her own lightweight jab inflicted some early pain and then levelled the seesaw encounter at 1-1. 

Williams`s blows, however, became too frequent and too heavy in the final games, with the weaponised serve pushing the world number 55 Riske back on her heels, leaving the Williams forehand to work like an old slugger`s right-hook. 

Having knocked out world number one Ash Barty in the last round and having spent over nine hours on court en route to the quarters - the longest path to the last eight of anyone since 2011 - Riske had shown a streak of pure Pittsburgh steel. 

But Williams is tennis tungsten, and recovered superbly from a brief wobble in which she lost the second set and fell a break behind in the third. 

She eventually charged over the finish line after more than two hours on court, bringing up match point when Riske netted a forehand and completing the job in typical fashion with her 19th ace of the match. 

"It was really satisfying; I wouldn`t have won that match a couple of weeks ago, every match here has really counted," said Williams whose time on court since the Australian Open in January has been limited by a niggling knee injury. 

"She has played so great and beaten so many great players here. I was really pumped, it`s for a place in the Wimbledon semis - it`s a long arduous road."