Chelsea remain winless in this season's Champions League after being held to a 1-1 draw at home to Salzburg in Graham Potter's first game as head coach.
The Blues slumped to a shock 1-0 loss at Dinamo Zagreb in their Group E opener last week, with that proving to be Thomas Tuchel's final match in charge.
Potter's tenure looked like getting off to a winning start against Salzburg when Raheem Sterling opened the scoring from Chelsea's first shot on target early in the second half.
But Salzburg, who also held Milan last week and are now unbeaten in nine games in all competitions, hit back through Noah Okafor in the 75th minute to leave Potter and his players frustrated.
Chelsea dominated the opening 45 minutes in the first meeting between these sides, but Pierre-Emerick Aubameyang and Mason Mount were wayward from the best of their chances.
The hosts were given a fright shortly before half-time when Benjamin Sesko forced Kepa Arrizabalaga into a low save from Salzburg's only effort of the first half.
Potter opted against changes at the break and was rewarded in the 48th minute as Mount's pass ran through to Sterling, who curled a delightful shot into the bottom-right corner.
Chelsea were unable to push on from that breakthrough goal, though, and Okafor slotted past Kepa to level up after Thiago Silva failed to cut out the danger prior to Junior Adamu crossing.
What does it mean? No magical start for Potter
Potter had six days to prepare for this match following the postponement of last Saturday's trip to Fulham and opted to tinker with the formation by going with a hybrid 3-5-2 – at odds with the 4-3-3 the team sheet suggested.
Chelsea may have dominated possession, finishing with 72 per cent of the ball, but only four of their 17 shots were on target and they gifted Salzburg their leveller.
The Blues find themselves bottom of Group E after two rounds of matches and are three points behind leaders Milan, whom they now face home and away.
Versatile Sterling strikes
As part of Potter's formation change, moving to something close to the system he regularly used at Brighton and Hove Albion, Sterling was tasked with playing in a left-sided wing-back role.
The England forward scored regardless, getting the Potter era up and running with a strike that took him to 250 club career goal involvements in all competitions (158 goals, 92 assists).
Salzburg profit from sloppy Silva
While not at their best, Chelsea looked comfortable enough when in the lead until some poor defending from Silva allowed Adamu to tee up Okafor for the leveller.
Salzburg forward Okafor has now scored five goals in his past six Champions League appearances – only Erling Haaland has scored more (eight) for Salzburg in the competition.
Key Opta Facts
– Chelsea have failed to win both of their opening two matches of a Champions League campaign for only a second time, and first since 1999-2000.
– Potter became the eighth English manager to take charge of a side in the Champions League, and the sixth of those eight to fail to win his first such match.
– Potter has failed to win his first competitive match in charge of a side for the first time in his managerial career, having won his first match as manager of each of Ostersunds, Swansea City and Brighton and Hove Albion.
– Sterling scored his 25th Champions League goal, now the second-most of any English player, behind only Wayne Rooney (30).
Chelsea's Premier League meeting with Liverpool has been postponed, so they now have a long wait before facing Crystal Palace. Salzburg are at home to Rapid Vienna in the Austrian Bundesliga on Sunday.