Nemanja Matic scored a first-half header as Chelsea edged out Sporting Lisbon in a breathless encounter to go top of Champions League Group G.
Brimming with pace and purpose, Chelsea almost took the lead inside two minutes when Diego Costa raced clear but Rui Patricio smothered his effort.
Andre Schurrle wasted several openings before Matic rose to loop a Cesc Fabregas free-kick over Patricio.
Sporting improved after the break but Chelsea held on for an important win.
Without Patricio's heroics and their own wasteful finishing, Chelsea could easily have won by a more convincing margin.
But boss Jose Mourinho, whose side were held 1-1 at home by Schalke in their first group game, will be nonetheless delighted to have picked up three points against a team that were unbeaten in 16 home matches in European competition.
Champions League Group G table
Played Won Drawn Lost GD Points
He will be equally pleased that Costa put his fragile hamstring through a full 90 minutes just three days after Chelsea's 3-0 Premier League victory over Aston Villa.
The Spain striker, who has scored eight goals in his first six Premier League games, was a constant menace and could have scored on at least three occasions.
He should have put his team ahead in the second minute when he received Fabregas's threaded pass but his low shot was saved by Patricio with his legs.
The keeper was on hand again to smother Schurrle's close-range effort after Oscar had located another gap in the Sporting defence.
Schurrle had an even better chance moments later when Costa's cut-back teed him up in front of goal, but the Germany international dragged his shot wastefully wide.
Chelsea captain John Terry became the sixth English player to make 100 appearances in the Champions League.
The other five are Paul Scholes, Gary Neville, David Beckham, Ashley Cole and Frank Lampard.
Chelsea's pressure finally told when they took the lead from a set-piece. Fabregas's delivery from the left found an unmarked Matic at the far post and the midfielder, who used to play for Sporting's arch-rivals Benfica, planted a header over Patricio.
Sporting were more energetic in the second half with Nani to the fore. The Manchester United loanee hammered one long-range effort wide and fired another into the side-netting.
In between, Chelsea again sprang the Sporting offside trap, but Patricio tore off his line to thwart Oscar.
In a frantic final 15 minutes there were openings at both ends.
Chelsea left-back Filipe Luis pulled a strike wide after a flowing counter-attack and substitute Mohamed Salah blasted at Patricio when he was through on goal.
At the other end, Nani curled a long-range shot narrowly past the post and Fredy Montero headed wide.
Chelsea clung on and will now turn their attention to Sunday's Premier League meeting with Arsenal at Stamford Bridge.
Chelsea manager Jose Mourinho:
"This is not knockout where goals are fundamental. This is points. We lost two points at home, we recovered that.
"Because of the other draw, we put ourselves not in a comfortable position, but in one where we can control our destiny.
"We play two games against Maribor. If we manage six points, that would be 10 and job done.
"Now we have just to focus on beating Maribor, which I believe is not easy. To draw in Germany means something."
Sporting manager Marco Silva:
"We mustn't forget the merit of the opponent. We didn't start in a strong manner, but the match balanced out. We were able to create some equality in the flow of the game, but then showed a lack of attention for Chelsea's goal.
"In the second half we had to take risks. We had some chances, probably Chelsea had more chances.
"Ultimately it was a great show. We were able to entertain our fans. I think they went home content.
"That's good tonic for the next game, which we must face with the same determination we showed in the second half."
Chelsea signed Matic from's Sporting's rivals Benfica for £21m in January 2014
Nani (r) was one of Sporting's best players against Chelsea
Rui Patricio (l) was inspired in the Sporting goal