South African Louis de Jager leads the D+D Real Czech Masters after a birdie on the final hole gave him a course record-equalling 64 and a one-shot advantage over two-time winner Thomas Pieters on day one.
The Belgian had looked set to lead after fighting off the challenge of defending champion Johannes Veerman until the Amecian dropped back into a four-way tie for third towards the end of his round.
Early starters Marcel Schneider, Jordan Gumberg and Tapio Pulkkanen set the clubhouse target at six under par after each shot 66.
German Schneider birdied the first four holes and added an eagle at 12, while Gumberg and Pulkkanen had six birdies apiece.
Pieters started well with birdies at the first three holes before picking up further shots at six and eight.
But a bogey six on 10 saw him drop back into a large group on four under. A birdie on 12 and 13, the latter following a fine tee shot, saw him join the leading group on six under.
An eighth biride of the day and third in a row on 14 meant Pieters had gone ahead for the first time on seven under.
Pieters made it four birdies in a row on 15 but finding water off the tee on the final hole left him needing to hole a 25 foot putt to save par but a bogey meant he dropped back to seven under and a lead of one.
De Jager had his first of seven birdies at the opening hole then three in a row from six to eight as he made the turn in 32.
Further successes at 10 and 11 were followed by one at 15 which drew him level with Pieters at the top of the leaderboard.
A birdie on the final hole was enough to give De Jager the lead by one shot after a round of 64 as he chases his first DP World Tour title.
Defending champion Veerman birdied his opening two holes and then had further birdies on six and nine to turn in 32.
Another birdie on 10 took the American to a tie for fourth on five under and a three at the next saw him turn the leading group into a four-way battle.
"I just wanted to fit in with the fancy dressers on the Tour..."
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Rory Sabbatini chats his attire, unusual golf bag and being back in Prague 💬#CzechMasters pic.twitter.com/aby40L2EM1
He then had the chance to claim the outright lead on 12 but his birdie putt lipped out to keep him on six under.
But Veerman's birdie on 15 saw him draw level with Pieters once more before a bogey on the next put him back in the chasing group.
Pars on the final two holes for a round of 66 meant he finished the day on six under par.
De Jager admitted he had not found it easy. He said: "It was quite tricky out there today, the wind was from all different directions but me and my caddie made some good calls out there.
Birdie
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Birdie
Birdie (200th this season)
Johannes Veerman moves into a share of the lead at -6 with a run of birdies around the turn 👏#CzechMasters pic.twitter.com/qpOZBl8Y5w
"I’ve been hitting the ball well, but I’ve gone back to old things, old tendencies that I keep falling back to. I worked a bit on those at the start of the week and I hit the ball really well today."
Pieters said: "I made some putts that me and my playing partners thought were going to miss today, the greens were getting very bumpy near the end. I think I got a bit of luck, put some good strokes on it. It was tough putting.
"All the lines off the tee – I’ve played well here in the past – but they just suit me. I’m excited to hit the tee shot on two, for example, just to get it as far down as I can. Then you leave a 40-yard up and down.
"It’s not like I’m hitting six irons to two feet, but the fast start was good. That four iron on three was really good. That’s a good birdie."