While the 22-year-old Swiss is the clear favourite and will take to Centre Court defending a 22-match unbeaten record on grass, Grosjean holds a 2-1 advantage in their previous meetings, all of which took place in 2001.

The last four has a familiar feel to it as only Croatia's Mario Ancic, who plays second seed Andy Roddick in the other semi-final, was absent from the same stage last year.

Ancic was the last player to beat Federer on grass, winning in three sets as a teenage qualifier in the first round at Wimbledon in 2002.

Two years on and the Croatian, now 20, has fulfilled that early promise by dashing British hopes with a quarter-final victory over Tim Henman and reaching the last four of a grand slam for the first time.

The man who grew up practising shots with compatriot and 2001 Wimbledon champion Goran Ivanisevic faces a tough challenge against the owner of the world's fastest serve.

American Roddick, like 10th seed Grosjean, has made it to the semis without dropping a set and is looking more and more at home on the lawns of the All England Club.

Ancic, though, will take confidence from taking a set off the U.S. Open champion in their only previous meeting, on grass at Queen's Club earlier this month.

Roddick won that match 7-6, 4-6, 6-4 en route to retaining the Stella Artois title and looks a good bet to reach his second Grand Slam final.