They sit three points ahead of the Italians at the top of Group B having won each of their three fixtures.
He added: "The other day [vs Rayo] we started the game very well, but then it was hard for us to play as we did in the previous matches".
Messi, 31, fractured his arm during a match against Sevilla at the Nou Camp on October 20 and has missed four games, including the 5-1 thrashing of El Clasico rivals Real Madrid. But wins, in any form, can not be overlooked.
Barca needed goals from Ousmane Dembele and Luis Suarez in the final three minutes to claim a nervy win over Rayo last Saturday.
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Dembele was introduced for the ineffective Rafinha early in the second period and, despite struggling to get into the game, made a telling impact with his late leveller.
"I have brought everyone available", Valverde said to reporters in his pre-match press conference. During the first game, we did not manage to keep the ball well enough to turn the game around. "We know they will score many goals together again".
"It will be hard because they're a courageous team with a way of playing that I love".
"Maybe more aggresive because they're at home".
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"We are a very inclusive community, and we care about all of our students", Ford added. Ford says two of the students are African-American, one is Asian and one is Hispanic.
Messi - who returned to training on Wednesday - is unlikely to be risked given the club's medical team have not cleared him to play, but will be on hand should Valverde feel the need to call upon him.
Barca were without a win in four league games and defensive errors looked set to play havoc with their title challenge.
"It's the right time to show what we're worth", said Spalletti, whose side are coming off a seven-match winning streak in Serie A in which they are in second place, three points behind champions Juventus.
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