India’s top singles player Sumit Nagal advanced to the singles quarter-finals of the Prague Open with a come-from-behind win over lower-ranked Jiri Lehecka.

Sixth seed and No 127 had to battle hard to prevail 5-7, 7-6(4), 6-3 in two hours and 21-minute second-round contest of the clay court event.

Nagal will meet three-time Grand Slam winner Stan Wawrinka in the next round. The Swiss survived a scare from Oscar Otte before winning 3-6, 7-5, 6-1.