Atletico Madrid's hopes of coming back against Chelsea in the Champions League on Wednesday may depend on Luis Suarez returning to form on his return to the country where he became one of the best in the world.
Atletico trail 1-0 after Olivier Giroud's bicycle kick lit up an uneventful first game at the Wanda Metropolitano last month and handed Chelsea a crucial advantage heading into this week's second leg.
And if they are to reach the quarter-finals with another upset like the one that knocked out Liverpool last year, Atletico are likely to need Suarez back to his best at Stamford Bridge.
The Uruguayan's form has matched his team's, with a slight downturn in recent weeks perhaps inevitable after such an impressive first half of the season.
Suarez scored 16 goals in his first 21 games while Atletico lost only one of their first 20 in the league, when a first La Liga title since 2014 seemed firmly within their grasp.
Yet they have won only three of their last eight and Suarez has scored only twice in that time, even if those two goals have come in the last three, against Real Madrid and Athletic Bilbao.
Certainly, there can be no room for complacency for Chelsea, who know only too well the damage Suarez can do after his hugely successful four seasons for Liverpool, when he scored 82 goals in 133 appearances.
"He is a natural-born striker," said Chelsea coach Thomas Tuchel before the first leg. "He has that certain mentality that only strikers have. This mentality to show his will, intensity and anger to score and score and score and is never satisfied. What a mentality, what a player."
Tuchel is such a fan he even tried to sign the 34-year-old for Paris Saint-Germain when it became clear he was on his way out of Barcelona last summer.
"There was a possibility," Tuchel said. "We heard the rumours he was about to leave Barcelona and who cannot be interested to sign one of the best strikers in world football, in history and the present?
"We tried our luck. We did not make it, he chose to stay in Spain with Atletico and again he proves his quality."
Suarez has history with Chelsea too, after one of his three biting incidents happened while playing against them for Liverpool in 2013, with Branislav Ivanovic that time the victim.
But without fans in the stadium and with a fresh crop of players, Chelsea will be focused completely on thwarting Suarez's threat to their goal while the striker will be hoping to end his own six-year wait for a Champions League goal away from home.
"For all the competitions, not just the Champions League, his presence gives us experience and leadership," said Atletico coach Diego Simeone last month.
"He brings confidence to our team and a lot of tension for our opponents because history shows this is a player who has a gift around the goal."
Suarez's 18 goals in 29 games this season means his switch to Atletico from Barcelona last summer has already been a triumph but there will be disappointment now if he does not end the season with a trophy.
Despite their dip, Atletico remain four points ahead of Barca in La Liga and it might be that a defeat to Chelsea could help their La Liga ambitions, with the Catalans being knocked out of the Champions League last week by Paris Saint-Germain.
Suarez will not relent. "My way has always been to be competitive, always wanting to prove myself," he said earlier this month.
"To come to a team like Atletico that hasn't won titles for a long time, to be able to win something is definitely one of the wishes I have."
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