Stanislas Wawrinka edges Ivo Karlovic in hard-fought clash

Stanislas Wawrinka has reached the quarter-finals of the Cincinnati Open after a hard-fought match against Ivo Karlovic that saw all three sets go to tie-breaks.

The giant Croat drew first blood after a tight first set in which neither player broke serve, coming off best in the tie-break with a tally of 7-2.

Both were also just as evenly matched in the second set, but this time the Swiss veteran came out on top with a narrow tally of 7-5 in the tie-break.

With all to play for in the third set, Karlovic once again took his opponent right to the end, but Wawrinka edged it in the tie-break to seal a narrow 6-7(2) 7-6(5) 7-6(5) victory after a gargantuan match lasting nearly three hours.