Colsaerts was five down after just nine holes to South African Branden Grace before eventually losing 4&3, while Poulter started with three straight birdies at the spectacular Thracian Cliffs but also carded four bogeys and a double bogey in a 3&2 defeat to Thongchai Jaidee.
Ryder Cup team-mates Francesco Molinari, Graeme McDowell and Peter Hanson fared better with wins over Henrik Stenson, Chris Wood and George Coetzee respectively, while Carl Pettersson beat Thorbjorn Olesen, Gonzalo Fernandez-Castano saw off Jamie Donaldson on the 18th and Richard Sterne halved with Bo van Pelt.
The good news for Colsaerts and Poulter is that the three-man group format allows them the chance to reach the last 16 with a win today, with Colsaerts actually progressing via a play-off last year after drawing one game and losing the other.
“It’s not often you lose in match play and everything is fine,” said Poulter, who refused to blame struggling with stomach cramps for his shock defeat.
“I got off to a great start with three straight birdies but made a few mistakes and gave him holes today, which you don’t do in match play. If you hit a couple of errant shots on this course you’re going to struggle to get back.”
Colsaerts was never in front against an inspired Grace, who holed from 45ft on the third for one of his five birdies on the front nine, but said: “I’m not worried because my game is so close to where it was the last two years. It’s just about inches here and there. I know if I play well tomorrow I am at least in a play-off and I feel like this course suits me as well as any other.”
Arguably the best game of the day saw Fernandez-Castano beat Donaldson on the last when Donaldson looked like escaping with a half after being four down with seven to play.
The Welshman birdied the 12th, won the 14th with a par and got back to one down with another birdie on the 16th after playing a recovery shot left-handed.
He then hit a superb approach to six feet on the 18th, but saw Fernandez-Castano hit his even closer to seal the win.
“I think on 16 I lost a bit of concentration after his tee shot ended up on the edge of the path and he had to play left-handed and he made a magnificent birdie,” Fernandez-Castano said.
“But I’m really happy, especially the way I played the last two holes, so we have to take the positives.
“Even though my match play record is not good, I’ve always enjoyed playing it and I think I’m good at it. I need to keep proving, especially to the new Ryder Cup captain, that I can play this format.”
Another player looking to impress Paul McGinley is Pettersson, an impressive 4&3 winner over Olesen who has taken up European Tour membership in a bid to finally qualify for the Ryder Cup.
Pettersson, who has lived in America since he was ten and took up US citizenship last year, would have qualified for the 2006 contest at the K Club if he had been allowed to rejoin the European Tour at the start of the selection process the previous year.
He would also have been a contender for the team last year, but did not want to play the minimum 13 European Tour events required for membership.
Biggest win of the day belonged to last year’s runner-up McDowell, who was three under par in beating Wood 5&3 and will be assured of a place in the last 16 before his second match this afternoon if Wood also loses to Stephen Gallacher this morning.
“It was important to get off to a good start,” McDowell said. “For the guys that lost today it’s not the end of the world, but to get the win under the belt takes the pressure off somewhat.”