Janko Tipsarevic has advanced to the fifth round of the Miami Masters after overcoming Grigor Dimitrov 7-6 6-2.
The Serbian took the opening set in a pulsating tie-break after both players had held their serve.
Tipsarevic found his rhythm in the second set, however, and proved too much for the Bulgarian after breaking him twice to take second set 6-2.
It is the third time in three matches that Tipsarevic has beaten Dimitrov in straight sets.
