Halle - Four-time winner Roger Federer outclassed Germany's Mischa Zverev 6-0, 6-0 on Friday to book his place in the semi-finals of the Halle Open.
The world number three will play the winner of the quarter-final match between Germany's Tommy Haas, who beat him in last year's final, and France's Gael Monfils.
The 31-year-old Federer wrapped up the first set in just 20 minutes then concluded the second - and the match - 39 minutes later against the world number 156.
The "double bagel" whitewash is the second of Federer's career. His first was inflicted on Argentina's Gaston Gaudio in the semi-final of the Shanghai indoor tournament on November 14, 2005.
In Halle, the Swiss was even more efficient than in his opening 6-3, 6-3 victory over another German qualifier, world number 166 Cedrik-Marcel Stebe, in 67 minutes.
Federer, who has won a record 17 Grand Slams, is still out to win his first trophy of the season and now has 41 wins and just five defeats on the grass at Halle.
Results from day five of the ATP Halle Open (x denotes seeding):
Roger Federer (SUI x1) bt Mischa Zverev (GER) 6-0, 6-0
Tommy Haas (GER x3) bt Gael Monfils (FRA) 6-7 (4/7), 6-3, 6-3
Mikhail Youzhny (RUS) bt Philipp Kohlschreiber (GER x6) 6-3, 6-2
Richard Gasquet (FRA x2) bt Florian Mayer (GER x8) 6-3, 7-6 (7/4)