Juan Martin del Potro overcomes plucky Radek Stepanek

Juan Martin del Potro has beaten Radek Stepanek in three sets to reach the quarter-finals of the Sydney International.

After taking the first set 6-4, the Argentine was forced into a decider when the Czech levelled 6-3 in the second.

However, the 2009 US Open champion clinched the third set 6-3 after two hours and eight minutes on court, setting up a meeting with Denis Istomin in the last eight.

The Uzbek defeated Russia's Dmitry Tursunov 7-6[5] 6-2 to seal his progress.