Romelu Lukaku's second-half header saved an under-par Chelsea as they began their Champions League defence with a 1-0 win over Zenit at Stamford Bridge
Lukaku brilliantly headed home Cesar Azpilicueta's deep cross (69) for his fourth goal in four appearances back at Chelsea, in a game where the European champions struggled to create clear-cut chances and one manager Thomas Tuchel admitted was "not easy" for Lukaku
Zenit nearly grabbed an equaliser late on as sub Artem Dzyuba failed to convert at the far post with the goal gaping, summing up a nervy and at times frustrating opening night in Group H for Tuchel's side
With Juventus winning 3-0 at Malmo, Chelsea sit second in their group, before going to the Italian side on September 29 for matchday two
 Tuchel's side remain unbeaten this season after five games in all competitions
Fireworks greeted the European champions before the game, four months after their triumph over Man City in Porto, but there was a lack of spark on the pitch for the first hour as the visitors frustrated Chelsea
Zenit were compact and disciplined in the first half as Chelsea struggled to create any chances of note, the hosts failing to register a shot on target until the 47th minute
Hakim Ziyech was wasteful, Lukaku wasn't being utilised and despite Mateo Kovacic's best efforts, the midfield were struggling to connect with the forward line
The game came to life in the second half from an unlikely attacking source as defender Antonio Rudiger burst forward 70 yards from defence, taking on two Zenit players before lashing a couple of yards wide from the edge of the box, a goal that would have brought the roof off Stamford Bridge
Rudiger was then imperious at the other end, denying Sardar Azmoun a shot on goal having been played through one-on-one with Edouard Mendy, as the German defender proved why he is now being regarded as one of the best defenders in world football
Lukaku barely had a sniff as the game approached the final quarter, but as he showed on Saturday in the 3-0 win over Aston Villa, the Belgian only needs one opening
Crossing from deep on the right, Azpilicueta's delivery was met by Lukaku at the far post, directing his header into the ground and beyond Stanislav Kritsyuk for his seventh goal in six games this term for club and country
 Lukaku, as he so often does, turned a decent delivery into a brilliant one
Chelsea smelled blood and looked for a second, but after several moments of pinball in the box, failed to find it, giving Zenit hope of an equaliser
And they nearly got it as Azmoun's centre from the right found Dzyuba on the stretch a few yards out, but the substitute could only get the faintest of touches on the stretch as the ball fell wide
Chelsea previous defence of a Champions League crown didn't go to plan - Roberto Di Matteo was sacked in November 2012 following a 3-0 defeat by Juventus that knocked the Blues out just six months after their triumph in Munich - but there's far more optimism that this side can progress with minimal fuss
 Their next game in Turin in two weeks will surely be their toughest test
"Lukaku is an outstanding centre-forward
 He didn't have a lot to work with, he didn't have a lot of chances, but the header was special
"They were efficient, Chelsea, and it was hard for them
 They have earned the reputation that teams will now come to Stamford Bridge, kick off and park the bus
 That's what happens when you are a top team
 Chelsea will face that, l would say, in every Champions League match they play until the quarter-finals
""The performance from Romelu was not easy
 We didn't create many chances for him but he's the type of guy who doesn't lose confidence and belief
 And that is why he is a world-class striker
"He's super important, it's as easy as that
 You don't find many strikers of his quality
 There are not many goals in football and goals change the momentum of the match
 It gives the whole team belief that one chance is enough for him to score
 So it's not only talent he brings, he brings belief and takes pressure off the shoulders of other guys around him
"He has the personality not to lose confidence
 He his at a very high level and we are very happy with to have him with us
"We did win also without Romelu and produced results
 But he was the type of profile we were missing, not just because of the talent but because of the personality
 He is such a humble guy, a super communicator in the dressing room, and that creates a certain energy around him in the team that we are proud of and what to have
"The spirit and atmosphere last year took us very far and it's important we have it again
 We have it with Romelu, he knows what the club is about
 He is here to help with his goals and if we miss him for one game, or hopefully not more games, we will try to find different solutions as we create chances
"But we have him and we are very pleased because he gives everybody around him confidence
 It is the best start for strikers to score
 There is no talk, no video, that can have the same impact
"September 29: Juventus (A) - kick-off 8pmOctober 20: Malmo (H) - kick-off 8pmNovember 2: Malmo (A) - kick-off 5
45pmNovember 23: Juventus (H) - kick-off 8pmDecember 8: Zenit (A) - kick-off 5
45pmChelsea now go to Tottenham in the Premier League on Super Sunday, live on Sky Sports Premier League at 4
30pm, before a Carabao Cup third-round clash at home to Aston Villa on Wednesday September 22 at 7
45pm
Their next Champions League game is at Juventus on Wednesday September 29 at 8pm
 Zenit host Malmo on the same day at 5
45pm
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