Novak Djokovic has advanced through to the quarter-finals of the Cincinnati Open after Nikolay Davydenko was forced to retire during their third-round encounter.
The Serbian second seed tore his Russian opponent apart 6-0 in the opening set.
However, Davydenko withdrew from the match before the start of the second with a shoulder injury, having called on his trainer during the break.
Next up for Djokovic is a match with Croatian 12th seed Marin Cilic.
