Darren Clarke, David Lynn and Charl Schwartzel were sharing top spot when rain interrupted the Joburg Open once again.
After an amazing 15 changes to the lead at the start of the third round the trio all stood 13 under par as they approached the turn.
Three other players - Lynn's fellow Englishman Danny Willett and Schwartzel's fellow South Africans Hendrik Buhrmann and Neil Schietekat - also had at least a share of first position for a while.
Lynn, seeking only his second European Tour victory in over 300 events, followed four opening pars with a bogey to slip back to 11 under, but chipped dead on the long sixth and played a superb approach to the 419 yard next for another birdie.
Vicar's son Willett, a teammate of Rory McIlroy at the 2007 Walker Cup, held the outright lead after three birdies in the first five, but bogeyed the short fifth and dropped another shot after driving into the water on the next.
Clarke, whose opening 63 on the adjoining West course was his lowest European Tour round since 1999, made his move with three birdies in four holes from fifth.
Schwartzel, winner of the Africa Open last Sunday and the pre-tournament favourite, continued to look solid and picked up birdies at both the par fives on the front nine.
Like the Fourth Test at the nearby Wanderers, the first two days were rain-affected and this time the sirens sounded at just before 1.45pm as a thunderstorm approached.
Because of the hold-ups the second round had to be completed at the start of the day, with the cut being confirmed at three under par and costing defending champion Anders Hansen his place in the event.
There were further changes when play continued after a delay lasting more than two hours.
Clarke three-putted the ninth, while Willett birdied it to rejoin Lynn and Schwartzel out in front on 13 under.
Lynn then three-putted the tenth and after Schwartzel had got up and down from a bunker to save par there Willett missed a five foot birdie chance.
Another bogey followed for Lynn after his approach landed inches from the water on the difficult 11th.
The title hopes of Willett and Lynn nose-dived when they double bogeyed the 12th and 13th respectively, but Clarke birdied the second of those.
It put him level with Schwartzel once more, but only for a few seconds as The Race to Dubai leader had hit a brilliant tee shot to four feet at the short 12th and with a two moved to 14 under.
Schwartzel had not dropped a shot since a double bogey at the 12th hole of his opening round on Thursday.