Local hero Nicolas Colsaerts was among the early leaders as the inaugural Belgian Knockout got under way at Rinkven International Golf Club.
The innovative format sees the 144-man field play two days of 18-hole stroke play, with the top 64 then advancing to a nine-hole stroke play knockout and the winner being crowned on Sunday after a total of 90 holes.
Belgian Ryder Cup star Colsaerts is one of the big draws this week and he did not disappoint the crowds on Thursday morning, making two birdies in his first nine holes to get to two under and join Oliver Farr, Lucas Herbert, Sam Horsfield and Phachara Khongwatmai at the top of the leaderboard.
There was then a group of nine players at one under playing the composite course in Antwerp.
Starting on the tenth, Colsaerts began his round with six straight pars but then picked up shots on the 16th and 18th to join the lead.
Welshman Farr also had birdies on the 16th and 18th in his first ten holes to go with a gain on the tenth and dropped shot on the 11th.
Australian Herbert arrived fresh off the back of a tie for third at the Rocco Forte Sicilian Open and he picked up shots on the first and third in his first six holes, with England's Horsfield making birdies on the first and fourth in his opening ten.
Thai Khongwatmai made birdies on the 12th and 14th in his first six holes.
French trio Benjamin Hebert, Romain Langasque and Clément Sordet, Danish pair Joachim B Hansen and Søren Kjeldsen, Swede Jens Fahrbring, England's James Heath, Malaysian Gavin Green and Belgian Christopher Mivis were the other players under par.