Surviving seeds Kevin Anderson and Adrian Mannarino showed no mercy Friday as they cruised into the South African Open semi-finals.

South African Anderson outclassed Slovak Karol Beck 6-3, 6-1 after Frenchman Mannarino ended the giantkilling run of Canadian Frank Dancevic with a 6-3, 6-2 triumph.

Izak van der Merwe kept alive hopes of an all-South Africa final in the ATP World Tour event at Montecasino entertainment centre north of Johannesburg by winning the opening quarter-final 7-6 (7/5), 6-2 against German Simon Greul.

India Davis Cup star Somdev Devvarman -- the sole Asian to make the last eight -- got his act together late in the duel to overcome Rik de Voest of South Africa 3-6, 7-6 (7/5), 6-1.

Anderson, a 2.3-metre 'skyscraper' seeded fourth and the highest ranked semi-finalist at 59, faces sixth seed Mannarino, eight places behind on the world rankings.

The other place in the Sunday final rests between Van der Merwe, 170 on the world listings, and reigning Commonwealth Games and Asian Games singles champion Devvarman, who is 60 places higher.

At stake is a 76,500-dollar first prize and 250 ATP points and history is sure to be created whoever makes the victory speech as none of the last four have won a World Tour title.

Jet-propelled serves whistling through the air 1800 metres above sea level once again proved a major factor with the form of top South African Anderson particularly impressive.

A record crowd for a quarter-final at the venue saw him comfortably win the opening set before a couple of early second-set service breaks by the local favourite reduced Beck to a virtual spectator.

Dancevic was a pale shadow of the player who eliminated top seed Feliciano Lopez of Spain and local Fritz Wolmarans in previous rounds and the longer the match progressed the more dominant 22-year-old Mannarino became.

Once Van der Merwe won on a first-set tiebreaker littered with mini-breaks, he looked set for victory as Greul failed to build on a bright start in baking early afternoon heat.

Devvarman, a quarter-finals loser to Spaniard David Ferrer last year, built leads in two sets only to lose the first and win the second via a tiebreaker before taking control as De Voest faded dramatically.