Fabrizio Zanotti edged his nose in front when the weather-affected second round of the Nedbank Golf Challenge hosted by Gary Player got back under way.
Zanotti was tied at the top of the leaderboard with Englishman Chris Wood when play was suspended at 14.08 local time due to the threat of lightning.
But the Paraguayan rolled in his two-foot birdie putt at the tenth when play resumed at 15.50 to get to seven under and take a one-shot lead.
The 33 year old began the day on two under par, two shots behind overnight co-leaders Felipe Aguilar, Ross Fisher and Jeunghun Wang, but found himself at the summit after making the first hole-in-one in the tournament's history at the fourth.
Zanotti notched back-to-back birdies at the first and second holes before safely parring the third.
He then holed a seven iron from 210 yards at the fourth to move to six under and establish a one-shot lead over the chasing pack.
George Coetzee carded three birdies in his opening six holes to take a share of the lead, and when Zanotti dropped his first shot of the day at the seventh, the South African was alone at the top of the leaderboard.
But Zanotti bounced back immediately, rolling in his eight-foot birdie putt at the eighth to return to six under.
He regained the outright lead when Coetzee carded a bogey at the eighth but Wood notched his third birdie of the day at the ninth to join him at the top just before play was suspended.
And Zanotti was on his own at the top once again when he fired his fourth birdie of the day at the tenth.
Wood, Wang, Fisher and Sweden's Alex Noren were Zanotti's nearest challengers on six under, with home favourites Coetzee, Jaco van Zyl and Louis Oosthuizen another stroke back.
