Juan Martin del Potro has recorded his first win at this year's ATP World Tour Finals with a resounding straight-sets victory over Janko Tipsarevic.
The Argentine world number seven was ruthless in the first set as he bludgeoned the under-par Tipsarevic 6-0.
There was slightly more resistance from the Serbian in the second, but Del Potro broke once to see out the match 6-4.
The defeat has all but ended Tipsarevic's chances of reaching the semi-finals, while Del Potro is still able to qualify for the last four when he takes on Roger Federer on Saturday.
