Chelsea have battled to a 1-0 win over Hungarian champions Videoton at Stamford Bridge thanks to a 70th-minute strike from Alvaro Morata.
The Spanish striker rescued his side by netting just his second goal of the season, and his first in seven games, to break down the visitors’ resolute defence.
Vidi made life difficult for Chelsea up until that point and nearly snatched a goal of their own against the run of play, forcing Maurizio Sarri to turn to Eden Hazard early in the second half.
Victory was all that mattered in the end, however, and the three points take Chelsea clear at the top of Group L ahead of their double-header against closest challengers BATE.
Chelsea made a bright start in their first ever home group game in this competition, with Willian and Emerson Palmieri flashing shots wide inside the opening 10 minutes.
The hosts’ first clear-cut opening fell the way of matchwinner Morata, who slotted wide from a one-on-one position once slipped through by compatriot Pedro.
It was a compliment to Vidi that Sarri was forced to turn to Hazard from the bench with just 11 minutes of the second half played.
Even the introduction of the in-form Belgian could not inspire Chelsea at first, though, and Vidi saw a couple of good openings come and go for Georgi Milanov, including a wayward shot from eight yards.
Chelsea looked a lot more comfortable for a large majority of the remainder of the match, coming close to a quickfire second through Barkley’s header from a Hazard delivery – the crossbar coming to Vidi’s rescue.
The three-time Hungarian champions could easily have snatched a late equaliser, however, as a big save from Kepa was required to push aside Istvan Kovacs’s outside-of-the-boot shot from the last meaningful act of the match.