Alvaro Morata ended his goal drought to earn Chelsea a 1-0 home win against Vidi in the Europa League.
The striker - without a goal since the middle of August - missed a great early chance but struck in the second half to put the Blues in a dominant position at the top of Group L.
Willian's flick-on gave Morata the chance and the Spain striker's instinctive finish flashed past goalkeeper Tomas Tujvel at Stamford Bridge.
Loic Nego had a series of chances for the Hungarian side, but Chelsea held firm to follow up a matchday one 1-0 win over PAOK with another narrow Europa League victory.
Morata had seven shots without hitting the target against PAOK and the striker missed another superb chance in the 16th minute.
Having beaten the offside trap to advance on goalkeeper Tujvel and after creating an angle for the shot, Morata somehow fired wide from eight yards out.
Despite Chelsea's dominance Vidi almost scored against the run of play before the break, Nego poking wide after a mix-up between Kepa Arrizabalaga and Andreas Christensen, then shooting straight at the goalkeeper from close range.
Nego was proving a significant threat and Kepa had to make an excellent save from his left-footed drive shortly after the restart to keep the scores level.
Such was Sarri's concern he sent on Eden Hazard for Pedro in the 54th minute, with Ruben Loftus-Cheek bending a shot narrowly wide soon after the Belgium star's introduction.
But Morata broke the deadlock in the 70th minute, Cesc Fabregas finding Willian in the box with the Brazilian's clever header slammed home by the striker for his first goal since scoring in a 3-2 win against Arsenal.
Substitute Ross Barkley almost marked his England recall with a flicked header, while Kepa made a vital late save from Istvan Kovacs, but one goal again proved enough for Chelsea in the Europa League.
What it means: Europa League an annoyance for Chelsea
Sarri named a strong team for Chelsea's opener, a 1-0 win at PAOK, but it was very much a second-string XI that took on Vidi. With his side flying high in the Premier League, it is tempting to wonder if the former Napoli coach would be happier if Chelsea did not qualify. Having been given such a seemingly straightforward group, though, the Blues will surely be progressing - it could affect their title hopes domestically.
Morata finally comes good
It looked set to be another frustrating game for Morata, who should have scored an early opener but somehow missed the target with the goal at his mercy. His confidence has obviously been affected by a poor run of form, but, to his credit, Morata - who was booked for dissent before scoring - kept going and he got the crucial goal. Perhaps his self-belief will now rise, which would be a big boost for Chelsea as the former Real Madrid and Juventus striker is a major threat at his best.
Nego misses costly for Vidi
For much of the game it was Nego offering the best goal threat, not Morata. But it was Morata who won the game for his side while Nego could not make his chances count. An opportunity late in the first half, when Nego shot at Kepa when he looked the favourite to score, will be rued by the Hungarian side's coach Marko Nikolic.
Chelsea head to Southampton in the Premier League on Sunday, with Vidi also on domestic duty the same day at home to MTK.