PSV Eindhoven took full control of Group L as last-gasp goals from Ola Toivonen and Tim Matavz condemned Europa League rivals Rapid Bucharest to a 3-1 defeat at the Giulesti Stadium.
Both sides had edged their opening fixtures 1-0, PSV against Legia Warsaw and Rapid at Hapoel Tel Aviv, but it was the Dutchmen who maintained their 100% record.
Dan Alexa put the home team in front against the run of play but the sides went in level after Wilfred Bouma touched home just before half-time.
That looked to be the last score of the game but the visitors found a late second wind, with Toivonen notching in the 88th minute and Matavz providing the gloss in added time.
Rapid took eight minutes to fashion a first chance but when they did, it could easily have yielded a goal.
Daniel Pancu was the man on the end of the move but he lifted the ball over the crossbar from six yards out.
Dries Mertens unsuccessfully attempted to lift the Eredivisie side, first taking aim from 25 yards and sliding his shot wide of the target, then seeing a counter-attack come to nothing.
Rapid could not hold PSV back, though, and Matavz was next to try and break the deadlock. But, after mis-hitting his first strike on goal, he hit an even better chance over from close range.
Chances continued to come and go, Georgino Wijnaldum joining the increasingly lengthy list of PSV players to miss the target.
After 28 minutes came the almost inevitable sting in the tail as Rapid scored with just their second opportunity of the match.
Pancu played creator, heading on Rui Duarte's corner and doing enough to divert the ball to Alexa, who nodded home.
PSV got themselves back into the game before half-time.
Kevin Strootman provided the free-kick delivery after Alexa's foul on Jeremain Lens and Bouma was the man in the right place to steer home from six yards.
The second half started with PSV trying, but failing, to regain their earlier dominance as the Romanians settled into a comfortable period.
After 63 minutes they produced a first clear chance of the second half, Rui Duarte's cross headed over by Pancu.
With a point apiece looking the likeliest outcome, Strootman again claimed an assist as he lifted the ball for Toivonen to head over the line.
Matavz then made it three for PSV when he swept home Mertens' cross from the edge of the area.