Roger Federer put his global army of "Fed-Head" fans through the wringer for four nerve-shredding sets before he kept alive his pursuit of a record eighth Wimbledon title with a 6-7 (7/4), 4-6, 6-3, 7-6 (11/9), 6-3 win over Marin Cilic in the quarter-finals on Thursday (AEST).Novak Djokovic's shock third round exit had raised hopes that this could be the week when the Swiss finally ends his four-year hunt for an 18th grand slam title, as the Serb had been the only man to beat him at the majors over the past year.
However, all those expectations appeared to be heading for the dustbin as Cilic stood one point away from victory - not once, not twice but three times in a pulsating fourth set that had everyone on the edge of their seats.
Three huge serves kept Federer alive - just - and he then produced the kind of form, and outrageous shots, that has made him the most successful man in tennis by stealing the tie-break 11-9.
An ace on his first match point finished off the job after three hours, 17 minutes of high drama and carried him into an 11th Wimbledon semi-final, and 40th overall in the majors.
"I knew I was in so much trouble in the third and again in the fourth," Federer said after walking off Centre Court to a standing ovation.
"It wasn't going well for me. So for me it was about staying in the match and somehow hope for his level to drop ... and maybe get a bit lucky. That's exactly what happened at 3-3, 0-40 (in the third set)," added Federer about the game where he saved three break points.
He will face another big-server, Canadian Milos Raonic, for a place in Sunday's final.
The sixth seed Raonic beat American Sam Querrey - who conquered Djokovic earlier in the tournament - 6-4, 7-5, 5-7, 6-4.
The other semi-final will pit Tomas Berdych (10) - who beat French 32nd seed Lucas Pouille 7-6 (7/4), 6-3, 6-2 - against Andy Murray.
Murray thrilled the home crowd with a five-set win over France's Jo-Wilfried Tsonga 7-6 (12/10), 6-1, 3-6, 4-6, 6-1 in the final quarter-final.