Pierre-Emile Hojbjerg rescued a point after the home side appeared to have clinched a shock victory.
An own goal from Loic Balde had put the Premier League side in the driving seat early on. But following some back and forth, Les Rennais equalized through Flavien Tait.
Although Spurs kept more of the ball, they struggled to carve out chances in the match. They were punished in the 71st minute by Gaetan Laborde, who pounced on a defensive lapse.
However, just five minutes later, Hojbjerg saved them the blushes with a goal and forced a draw. Yet Spurs fans won't be too happy with either the result or the performance.
Here are the player ratings for Tottenham Hotspur:
Pierluigi Gollini - 6.5/10
The Italian made a few smart saves in the match but stood no chance with Rennes' first-goal. Though he could've done better for their second as he spilled the ball right into the path of Laborde.
Matt Doherty - 6.5/10
No question about his work-rate, but Doherty's end product left a lot to be desired. His forward runs produced little of note and wasn't courageous enough to fight for the ball either. However, a good cross resulted in Tottenham Hotspur's goal in the first-half. Kudos to that.
Japhet Tanganga - 6/10
He was really conservative in the first-half in the sense of not going all in against Rennes and their attackers. But looked far more confident and robust after the break.
Joe Rodon - 7/10
Arguably the best defender for Tottenham Hotspur on the day, Rodon swept everything in front of him and was formidable in the air too. Strong return from injury for the Welshman.
Ben Davies - 5.5/10
He left plenty of gaps at the back for Rennes to exploit and couldn't muster anything meaningful on the attacking front either.
Tanguy Ndombele - 7.5/10
Dangerous off the ball, threw his weight around in defense, created a few chances and ran his socks off. Ndombele was a machine today. An island of excellence in a sea of mediocrity.
Oliver Skipp - 6/10
He played a big part in the build-up to Tottenham Hotspur's opener with a nice pass for Kane. But that was his only notable contribution as Skipp was otherwise run over in midfield.
Lucas Moura - 7/10
Moura was a bright spot in the attack for Tottenham Hotspur and forced an own goal in the first-half with a rasping shot. He seemed like the most likely source for more goals but saw his evening cut short with an injury.
Bryan Gil - 6/10
Tottenham Hotspur's new boy was left chasing shadows for most of the game as he well and truly struggled for control in midfield. His crossing ability needs to sharpen up.
Steven Bergwijn - N/A
The Dutchman went off injured very early on into the match as Tottenham Hotspur were dealt a blow.
Harry Kane - 6/10
He set up Moura for the own goal with a pass but no one else in the side created anything for him, prompting the striker to drop back and help in chance creation.
Pierre-Emile Hojbjerg - 7.5/10
The Dane made a few sideways passes and struggled to break down Rennes. But he slowly grew into the match and scored the equalizing goal for Tottenham Hotspur. Their unlikely hero.
Emerson Royal - 6/10
He came on for the injured Moura and provided a good attacking outlet but wasn't lethal enough. Rennes dealt with him well.
Dane Scarlett - 6.5/10
The youngster had an impressive cameo, working hard off the ball and making some lovely movements to trouble Rennes.
Dele Alli - N/A
He merely came on to see the game off.