Jo-Wilfried Tsonga showed great resilience to fight from back from a set down to beat Roger Federer 3-6 6-2 7-5 in an enthralling quarter-final at the Monte Carlo Masters.
Tsonga suffered a last-eight exit at the hands of Federer in the 2014 edition of this competition and, despite losing the opening set to the four-time runner-up, he gained vengeance to progress to the semi-finals.
The world number three, competing at his first tournament since the Australian Open having overcome a knee injury and bout of illness, showed signs of rustiness and paid the price for uncharacteristic errors.
It was Tsonga who had more mistakes in his play during the early stages, but, after a string of forehand errors, he played a superb thumping cross-court winner to immediately get back on level terms at 2-2.
World number nine Tsonga missed an opportunity to break back at the first opportunity after dropping serve again in game seven, and the Swiss closed out the opening set.
The Frenchman responded brilliantly and won the first game of the second set, though he required four break points to do so.
Tsonga's developing confidence was evidenced by an exquisite drop-shot in the fifth game, and he followed it up by punishing Federer for sending a smash to hold serve wide by moving three games clear.
The 17-time grand slam champion threw away his racket after suffering a third break of the set, Tsonga consistently finding the lines to force a decider.
Federer let Tsonga off the hook early in the third set with two forehand errors at deuce costing him the chance to take a 2-0 lead, and the first break point did not come until the 11th game.
The Frenchman claimed it with a brilliant drop-shot and he served out the set, to book a meeting with either Gael Monfils or Marcel Granollers.