Rahul top scores for LSG but Samson and Jurel get RR home with their 121-run stand
World number one Federer nows faces either Robin Soderling, the Swedish fifth seed who he defeated in the final last year, or Croatian 10th seed Marin Cilic for a place in the semi-finals.
The great Swiss has never lost to either man in 13 meetings.
On Sunday, Federer was barely troubled by his compatriot, easing to a fifth career win in six clashes in five minutes short of two hours.
Wawrinka, who teamed up with his friend to win 2008 Olympic gold in Beijing in what he described as the the greatest night of his life, was broken in the third and ninth games of the opening set.
The 25-year-old achieved his first break of the contest in the opening game of the second, before Federer levelled in the eighth.
Wawrinka, bidding to reach a first Grand Slam quarter-final, got to 5-5 in the tie-break, but a terrible backhand volley was dumped in the net with Federer out of position.
That gave Federer set point and he was handed the second set when a dispirited Wawrinka netted again with a second service return.
Former Roland Garros junior champion Wawrinka angrily destroyed his racquet in the Paris dirt out of sheer frustration and picked up a code violation for his troubles. on his way to another comprehensive victory.
Later on Sunday, British fourth seed Andy Murray faces Czech 15th seed Tomas Berdych for a place in the last four.
His afternoon went steadily downhill, with Federer quickly stretching to a 5-1 lead in the third set
Eighth-seeded Jo-Wilfried Tsonga, the last French player still in the singles competition, takes on Russian 11th seed Mikhail Youzhny.
Rahul top scores for LSG but Samson and Jurel get RR home with their 121-run stand
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