LONDON (THE GUARDIAN) - Diego Costa has been labelled a "fraud" by Paris Saint-Germain's official Twitter feed before Wednesday's second leg of the Champions League knockout tie against Chelsea, with the French club's manager, Laurent Blanc, having warned his players not to be provoked by the Spain striker.

PSG's official account tweeted a Vine on Tuesday afternoon with the supporting video flicking through various masked movie characters and superheroes, from Batman to Zorro, Spider-Man to Darth Vader, Iron Man to Kylo Ren. Among them was an image of the Brazilian-born Costa sporting his own protective mask, with the strap-line across the bottom of the tweet reading "Spot the fraud".

The message had been a follow-up to a similar tweet asking followers to "spot the real hero", with a photograph of Thiago Silva celebrating after last season's tie between the teams at Stamford Bridge having been inserted among the pictures.

While the message was designed to be as humorous as it was provocative, the prospect of confronting Costa has occupied Blanc's mind in the build-up to Wednesday'ssecond leg, with the PSG manager having made a point of telling his players to keep their cool in south-west London.

"There are two facets to Diego Costa: the player and the man," said Blanc, whose team had been reduced to 10 men by Zlatan Ibrahimovic's dismissal in the corresponding tie last season , only to prevail on away goals.

"The player I like very much, a centre-forward who can score a lot of goals, has good movement, who works hard for the team. I'm a big fan of the player. But we also know the man, a man who likes contact, challenges, even provocation at times. That's part of his game. We saw that last year and he's a player who always performs like that. He doesn't just reserve that for matches against PSG. I've told my players not to respond.

"We have to keep cool in the face of provocation, even if we have Brazilian players across our back-line. But we'll need all our strengths at our disposal in a tight game. We need to stay with 11 on the field and enjoy a good game, so we can't respond to any provocation, be it from Diego Costa or anyone else. We were made to pay with that a bit last year and, this year, it could be even more difficult."

Costa, who has been wearing the mask after breaking his nose in an accidental training ground clash with Fikayo Tomori last month, is expected to be fit to feature against the runaway Ligue 1 leaders despite missing Saturday's draw with Stoke with a tendon problem in his calf.

The 27-year-old, as anticipated, did not complete the training session at Cobham on the eve of the tie but Chelsea, who will also have Pedro restored to the squad after hamstring trouble, in need of him to impress against Thiago Silva and David Luiz.

The striker is looking to improve upon a personal record of one goal - against Maccabi Tel Aviv in September - in 14 Champions League games for the London club, but can at least point to 10 in 14 appearances under Guus Hiddink as evidence of improved form.

"He has behaved very well (for me) and I'm very proud of him and the way he's playing," said the interim manager. "He's not going over the edge, but he likes to fight in the real way (allowed by) the game, and that's what we like. I protect him and support him when he's doing what he's done in my period at Chelsea."

Reports in Italy suggest the prospective new permanent Chelsea manager, Antonio Conte, will be in London and may seek to attend the game - his Italy midfielder Marco Verratti may begin on the bench for PSG after a groin injury - as the hosts attempt to prolong their involvement in European competition by overturning their 1-2 deficit from the first leg.

"Everyone knows where Chelsea's season is headed, coming from a difficult situation in December when we were very close to the relegation zone," added Hiddink.

"And the team responded, got the points, and are now mid-table in the Premier League. Of course this was a target, a soft target, for a club of the standard of Chelsea. But we did that in a relatively short time and now we have a new target which can and must be (winning) the FA Cup and Champions League. Success could give another image to Chelsea's season."