PORTO keeper Diogo Costa hinted he knew about Arsenal's "weaknesses" before their win in the Champions League.
The Portuguese side claimed a dramatic 1-0 victory over the Gunners in the first leg of their last-16 tie on Wednesday evening as Galeno struck a 94th-minute winner.
The defeat will come as a shock for Mikel Arteta's men - who went into the clash on a five-game winning streak.
But the result will not be a surprise to Porto shot-stopper Costa, 24, who mysteriously spoke about Arsenal's "weaknesses" in the lead-up to the game.
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During his pre-match press conference, the keeper said: "We are prepared for everything Arsenal can do, both offensively and defensively.
"Everyone has their weaknesses, they havenât faced FC Porto yet and they will certainly have their difficulties.
"Itâs a very offensive team with some weaknesses that we will exploit to the fullest and we will do everything we can to come out with the victory.
âThey have weaknesses, of course I wonât say what they are, but I guarantee that we will do our best to win.
"If they are favourites they have to demonstrate it."
Costa did not face a single shot on target from Arsenal on Tuesday night.
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But Arteta's side will still be favourites to progress through to the quarter-finals.
The second leg will take place at the Emirates on March 12.
Arsenal have not been in the Champions League knockout stages since the 2016/17 campaign.
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And they have not reached a quarter-final since the 2009/10 season when they were beaten 6-3 on aggregate by Barcelona.
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