Cincinnati, August 18: World number two Roger Federer posted his second win of the day, amid a lightning fear interruption, to reach the semi-finals of the ATP-WTA Cincinnati Masters on Friday.
The seven-time champion beat fellow Swiss Stan Wawrinka 6-7 (2/7), 7-6 (8/6), 6-2.
The match was interrupted for 21 minutes with players being sent off court and crowds told to seek shelter as a storm cell passed near the site.
But after the pause, the pair came back out, with Federer finally securing the first break of the match on his seventh chance to take a 4-2 lead over his longtime rival.
Federer closed out victory two games later and will face David Goffin after the Belgian beat Juan Martin del Potro 7-6 (7/5), 7-6 (7/4).
Federer began his day by beating Leo Mayer 6-1, 7-6 (8/6). (AFP)