The Englishman started the day with a three-shot lead and stretched it to four after four holes, but a severe wobble on the turn caused him to fall off the top until a birdie on the final hole left him tied at 12 under with Italian Guido Migliozzi.
Kanter was one of the first players to switch to LIV Golf in 2022, but has spent the past two seasons as a reserve for the Saudi-funded Independence team and is now back playing golf in his homeland.
He has finished second four times on the DP World Tour, including in Mauritius before Christmas, but he doesn't think that was the reason as he saw his 36-hole advantage evaporate in Hamburg.
“I really want to win,” he said. “I have nothing to lose and nothing to worry about in this regard. I'm just going to try to win the tournament.”
“I feel like I tried to do that today. There were times today where I felt like I might have lost that round, and it turned into two, three over. Hopefully that round was the toughest round I've ever had.”
After two-putting for birdie on the fourth hole, he missed a short putt on the eighth and dropped a tee shot on the 10th for double bogey before fighting back on the 11th and final hole.
Migliozzi, who had six birdies in a bogey-free 67, tied for first with Canter, one shot ahead of Denmark's Niklas Norgaard, who shot 71.
Tom McKibbin of Northern Ireland, who made four straight birdies on the back nine to finish four shots behind the leader at 71, will have a chance to defend his title.