Janko Tipsarevic and Rainer Schuettler lost first-round matches as seeded players continued to tumble out of the SA Tennis Open on Wednesday.
Half of the eight seeds have failed to win their opening matches at Montecasino.
Third-seeded Tipsarevic of Serbia was beaten by Jesse Huta Galung of the Netherlands 6-7 (4), 6-4, 7-6 (4) in a rain-delayed match held over from Tuesday.
Tipsarevic missed seven of 10 break points and saved just one from five on his own serve to go down in 2 hours, 43 minutes.
The match was level at 3-3 in the third when it was suspended on Tuesday, but Huta Galung returned to edge Tipsarevic in a deciding tiebreak.
The seventh-seeded Schuettler of Germany followed suit as he wasted an early lead in falling to Go Saeda of Japan 3-6, 6-4, 6-4.
Also, Dudi Sela of Israel got past Edouard Roger-Vasselin of France 1-6, 7-5, 6-4 in another match held over from Tuesday.
South African wild card Fritz Wolmarans hit 25 aces to beat Dutchman Igor Sijsling 4-6, 6-3, 6-4 and Slovakia's Karol Beck recorded a straight sets win over Argentine Brian Dabul.
Defending champion and top-seeded Feliciano Lopez of Spain was at one set-all with Frank Dancevic of Canada in his opening match when another rain shower held up play.