Switzerland's Roger Federer plays a shot against Italy's Lorenzo Sonego during their first round match of the French Open tennis tournament. (AP Photo/Michel Euler )

Paris - Roger Federer marked his return to Roland Garros after a four-year absence with a straight sets win over Italy's Lorenzo Sonego on Sunday (May 26), admitting he "felt on edge", as Angelique Kerber's hopes of completing a career Grand Slam suffered a quick kill.