Roger Federer has reached the Qatar Open semi-finals following a tough test against Andreas Seppi.
The world number three, who won his last 17 matches in 2011, clinched the lead comfortably in Doha with a 6-3 winning set.
While Federer looked likely to take the match with ease, his 27-year-old Italian opponent fought back and pushed the former world number one to take the second set 7-5.
The duo went into the final set on equal terms but Federer managed to put his stamp on the court and smash his way to the semi-final with a 6-4 win.
Federer will face French pro Jo-Wilfried Tsonga in the semi-final.
