Juan Martin del Potro made easy work of John Millman in their Mercedes Cup second round match in Stuttgart on Thursday (9th June), while Marin Cilic was way off form as he slumped to a straight-sets defeat against veteran Radek Stepanek.

Wild card Juan Martin del Porto defeated Australia's John Millman 6-4, 6-4 in Stuttgart to reach the last eight of the Mercedes Cup.

While the victory was rather routine, del Potro showed his compassionate side after he won a point when Millman slipped and fell in the second set's penultimate game.

Unfortunately for Millman, that break point made it 5-4 and gave del Potro the chance to serve for the match.

Del Potro will meet fourth-seed Gilles Simon in the quarter-finals.

Meanwhile, second seed Marin Cilic crashed out after a lacklustre display against veteran qualifier Radek Stepanek.

Stepanek's 7-6, 7-5, victory arrived despite the Czech firing fewer aces, 10 to 12, and serving more double-faults, 6-1.

The Croatian lost both sets through unforced errors - the first when he completely missed a simple return in the tie-break and the second by hitting another routine ball into the net.

Stepanek meets seventh-seed Philipp Kohlschreiber in the next round.