Barcelona's stars have stopped being surprised by Lionel Messi's continued brilliance, according to midfielder Sergio Busquets.

The Argentinian superstar has once again been in imperious form this season, scoring 43 goals in 40 games across all competitions.

Busquets has played alongside the 31-year-old for more than a decade and says there is nothing Barca's players have not seen the "unique" Messi do.

"We have the good fortune to train with him every day," he told the Daily Mail.

"I've spent the last 11 years with him, so you get that greater concentration of him doing these things.

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"We're not quite as surprised by it all. There isn't a goal he's scored on the pitch that we haven't seen in training and he's also repeating goals he has scored in previous seasons. He is unique."

Barcelona takes on Manchester United in the first leg of its Champions League quarter-final on Wednesday – the first meeting between the two since Barca's 3-1 win over the Red Devils in 2011's final at Wembley.

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Busquets looks back fondly on that game and believes it represented the "ultimate high point" of Pep Guardiola's trophy-laden reign of the club between 2008 and 2012.

"It was the best performance in the Pep Guardiola era," he said. "It was the pinnacle of everything we were achieving at the time.

"It was a period when our success seemed at its most emphatic and that game was the perfect demonstration. The idea of how we wanted to play and our superiority on the pitch was clear. It was the ultimate high point.

"Sometimes you can feel that frustration from the other team when you are so on top. We had prepared very well and caused them a lot of harm, just keeping the ball and with them running after it a lot."