Roger Federer has advanced through to the last 16 of the Cincinnati Open after edging past Vasek Pospisil in three sets.
The world number three looked on course for a simple passage through to the next round when he edged the opening set on a tie-break, but his Canadian opponent found a way back into the match in the second.
After the opening 10 games were dominated by serve, Pospisil broke Federer's serve to take the match into a decider as the world number 46 threatened to pull off a major shock.
However, Federer regained his composure to break twice in the third to record a 7-6 5-7 6-2 win to register his 300th victory at a Masters Series event.
Federer will now play either Roberto Bautista Agut or Gael Monfils on Thursday.
