The early pace was set by Australian Matthew Zions and Belgian Nicolas Colsaerts when the Volvo Golf Champions began at Fancourt.
With a restricted field of 35 players chasing a first prize of €350,000, the pair moved to three under par to lead Thomas Aiken and Colin Montgomerie by one.
Zions, who qualified by capturing the St Omer Open when all the stars were away at the US Open, had three birdies and two bogeys in his first eight holes after teeing off on his own because of the odd number of players.
Big-hitting Colsaerts birdied the short second as he tried to make his mark at yet another Volvo-sponsored event. He won the Volvo China Open and then reached the semi-finals of the Volvo World Match Play in Spain.
Open Champion Darren Clarke, Masters Tournament champion Charl Schwartzel, Ernie Els and, because players with ten or more European Tour victories qualified as well as all winners last season, Padraig Harrington, Montgomerie and José María Olazábal were all in a star-studded field.
Zions led on his own when he picked up another birdie on the long ninth to turn in a two under 34.
At 366th in the Official World Golf Ranking he was not the lowest-ranked player taking part, though. That was Olazábal at 596th, but the double Masters Tournament champion birdied the opening hole - and so did 313rd-ranked Montgomerie.
Colsaerts rejoined Zions when he closed the outward half with back-to-back birdies after bogeying the sixth.
Although Zions added another birdie on the 12th he lost top spot as Colsaerts made it four birdies in a row from the eighth.
Leading the home challenge - eight South Africans had qualified - was Aiken after three birdies in the first five, while Montgomerie went to two under at the third and fellow Scot Paul Lawrie was also only two behind following an eagle at the 568 yard ninth.
