The Uruguay forward, who has frequently been criticised by French media, fired a low angled shot past goalkeeper Thibaut Courtois in the 78th minute after John Obi Mikel had cancelled out Zlatan Ibrahimovic’s opener at the end of the first half.
PSG, who did not appear shaken by the scandal surrounding defender Serge Aurier after he was suspended by the club for insulting coach Laurent Blanc and several team mates, knocked Chelsea out on away goals at the same stage last year after the Blues prevailed the previous season in the quarter-finals.
It was Chelsea’s first defeat in 13 games since Dutchman Guus Hiddink took over from the sacked Jose Mourinho, but the London club were a tough nut to crack and they will fancy their chances in the return leg at Stamford Bridge on March 9.
With Chelsea’s captain John Terry ruled out with a hamstring injury, Branislav Ivanovic started in central defence and wore the skipper’s armband.
Marco Verratti started for PSG having just recovered from a groin injury, while Blanc chose to field Marquinhos on the right of defence in place of Aurier.
PSG pressed high up the pitch from the start and Verratti forced Courtois into a good early save with a fierce, low 20-metre shot.
The home side enjoyed plenty of possession as they imposed themselves on the game but Chelsea were tight in defence.
Swedish striker Ibrahimovic, who was sent off last year in the second leg of the last 16 tie, was shown a yellow card in the 19th minute for treading on Obi Mikel’s ankle.
Chelsea had the best chance midway through the first half when striker Diego Costa’s header from point-blank range was instinctively palmed on to the bar by PSG keeper Kevin Trapp.
Ibrahimovic broke the deadlock six minutes before halftime with a low free kick that was deflected past the wrongfooted Courtois by the heel of Mikel, who had fouled Lucas.
But Chelsea hit back in added time before the interval when Costa deflected a corner kick into the path of Mikel, who controlled the ball before firing home his first goal in 14 months and only his second ever in the competition.
PSG, who had not conceded at home in the Champions League this season, resumed their domination after the break with Angel Di Maria’s free kick parried away by Courtois in the 65th minute as the visitors held firm, hoping to catch PSG on the break.
Lucas was replaced in the 72nd by Cavani after another performance by the Brazilian in which he showed his skills but not the required finishing of a goalscorer.
The substitute had an immediate impact, collecting Di Maria’s perfect pass on the right and scoring with a low angled shot through the legs of Courtois after evading Ivanovic.
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