Jose Mourinho's side tasted defeat for the first time this season on Saturday, going down 2-1 at Newcastle United in the Premier League.
That ended a club-record-equalling 23-match unbeaten run, which stretched back into the 2013-14 campaign.
Chelsea's previous loss came in the semi-final second leg of last season's Champions League, when Atletico Madrid came away from Stamford Bridge with a 3-1 success back in April.
Having already secured progress to the last 16 as winners of Group G, Chelsea face a Sporting side who need a point to clinch their own qualification on Wednesday.
And goalkeeper Thibaut Courtois insists there is not undue concern in the Chelsea dressing room following their loss at St James' Park.
"Obviously we are disappointed but we have to takes the positives, we are still top of the league and we've had a great start to the season," Courtois told the club's official website.
"Okay, this was our first defeat but we have to keep working hard and things will go better for us again.
"We are confident that if we work hard in training and learn from our mistakes we will win again."
The fitness of Diego Costa remains a huge talking point at Chelsea, and it remains unclear whether Mourinho will risk his first-choice striker against Sporting with a league clash against Hull City to come on Saturday.
"He has to improve his condition," Mourinho said. "He was injured and had many doubts because he went a long time without training.
"Obviously that must have an effect on a player in the way he runs, the way he moves and in his co-ordination. I don't think there is any problem but he has to recover."
Sporting have a major injury doubt of their own, with the club announcing that on-loan Manchester United winger Nani had picked up a thigh injury in the 3-1 win at Boavista on Friday, rendering him unlikely to feature at Stamford Bridge.
That victory was Sporting's fourth in succession in all competitions, and another win in west London would see Marco Silva's men move into the knockout phase with a spring in their step.
Chelsea midfielder Nemanja Matic scored the winner in the reverse fixture back in September, and the Serb comes back into contention after missing the Newcastle trip through suspension.
Sporting defender Cedric, meanwhile, will miss the clash after picking up his third booking of the group stage in the 3-1 home win over Maribor on matchday five.
