United have experienced a revival under interim manager Ole Gunnar Solskjaer, who took over at the club after Jose Mourinho was sacked in December, and remain in the hunt for a top-four spot in the Premier League in addition to their last-eight place in Europe.

However, Pochettino, who has been linked to the United job since Mourinho's departure, told reporters in Barcelona that the Red Devils still have some climbing to do in order to reach Lionel Messi & Co.

"I think the Manchester United team have been built during the past few years to win big things," Pochettino said, when asked to comment on the tie. "But winning important competitions such as the Champions League or the Premier League always depends on small details.

"Of course they have the players that are capable of making things difficult for Barcelona. But I think Barcelona are one step higher than Manchester United."

The former Espanyol player and manager added: "If there is a favourite team to win the Champions League, it is Barcelona.

"[Barcelona manager] Ernesto Valverde is doing a great job. Then they have players of an extraordinary level. And then they have Leo Messi. Then you have teams such as Manchester City or Juventus that will always have chances to win the competition because they are teams designed to do that."

Pochettino, whose Spurs side drew Manchester City in UCL the quarterfinals, was seen as the early favourite to take over on a permanent basis at Old Trafford before Solskjaer's stunning run of results made him the only serious candidate for the job, sources told ESPN FC last month.

Despite the club's determination to seek a high-profile, experienced coach to replace Mourinho, sources said that Solskjaer moved ahead of Pochettino and Juventus coach Massimiliano Allegri -- neither of whom have so far been approached about the United job.