Eden Hazard was accosted by a shirt-seeking supporter at the full-time whistle of Chelsea's 2-1 win at Malmo, but downplayed the disturbing incident.
The culprit's grip was released only when the Belgium forward handed over his shirt and UEFA are likely to investigate.
The fan, one of at least four from the home stands who encroached on to the playing surface, was escorted off by stewards, holding the shirt.
Hazard appeared unnerved, but later brushed off the moment.
"It's not an incident. He just asked for my shirt," said Hazard, who came on as a second-half substitute in Thursday night's Europa League last-32 first leg in Sweden.
Chelsea responded from their embarrassing 6-0 mauling at Manchester City, but were less than convincing and received a stark warning from head coach Maurizio Sarri afterwards.
Chelsea appeared to be coasting at 2-0, through goals from Ross Barkley and Olivier Giroud, but Anders Christiansen's strike 10 minutes from time means the Blues' progression to the last-16 is no formality.
Two away goals and a lead to take back to the Bridge! 👍#MALCHE pic.twitter.com/4vJjHIlqhb — Chelsea FC (@ChelseaFC) February 14, 2019
Sarri's future remains in doubt ahead of a crucial week: Monday's FA Cup tie with Manchester United, next Thursday's second leg with Malmo and the February 24 Carabao Cup final with City. The Wembley date is followed by the Premier League clash with Tottenham.
The 60-year-old Italian said: "If we concede a goal like this to a team like Manchester City or United or Tottenham, then you risk conceding three goals in 10 minutes. So we have to do better, I think.
"We need to have continuity and consistency, I think, in the mental condition to be able to approach every match with the same level of application, determination and attention.
"You know very well that, if you are in bad mental condition in England, in 10 days you can lose three or four very important matches.
"So we need consistency. We have to approach every match in the same way. It's not easy, but we have to try."
Sarri was content with the performance, which saw Chelsea's first away goals in 2019 after losses to Arsenal, Bournemouth and at the Etihad Stadium.
"I am happy because we played with a very good level of confidence," Sarri added.
As well as the small pitch invasion, UEFA is likely to scrutinise Malmo supporters' use of flares and the throwing of drinks over the partition between home and away fans.
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