FILE - Chelsea boss Mauricio Pochettino (L) and Manchester United manager Erik Ten Hag last clashed in 2019. Photo: AFP
United suffered another setback in their spluttering campaign when they were beaten 1-0 at Newcastle last weekend.
The loss, which left United five points adrift of the Premier League's top four, came just days after they blew the lead in a damaging 3-3 draw at Galatasaray in the Champions League.
Ten Hag's men are in grave danger of being eliminated from the Champions League in their final group-stage match against Bayern Munich next week.
But before then they must fight to get their domestic form back on track, with Chelsea visiting Old Trafford before United host Bournemouth on Saturday.
Despite United's struggles, Chelsea boss Pochettino is adamant they remain a side to be feared.
"I wouldn't say it is a good moment to go there. We're going to face a team that's going to be tough because they want to win," Pochettino told reporters on Tuesday.
"They have very good players. They have pace with their offensive players and so we cannot allow them to transition.
"I think we need to be clever because they have pace through Marcus Rashford and Alejandro Garnacho who can transition really fast.
"We need to try to dominate and put pressure by playing in their half. That will be the challenge for us."
Chelsea are five points behind United after a slow start of their own this term.
Pochettino was linked with becoming United manager prior to Ten Hag's appointment last year.
He refused to be drawn on whether he was happy to have avoided the myriad of on and off-pitch problems that have hampered Ten Hag.
"You try to make me talk too much! I don't want to make a mistake. I'm not the person to talk about what is going on at different clubs. I'm happy here in this project," he said.
The Argentine eventually took over at Chelsea ahead of the current campaign and Wednesday's clash will be his first meeting with Ten Hag since Tottenham's dramatic 3-2 Champions League semi-final win against Ajax in 2019.
"He's a fantastic coach. I remember we faced him when I was at Tottenham in the semi-final of the Champions League against Ajax," Pochettino said.
"I think everyone was talking about him and Ajax so for me he's a fantastic coach and a great manager."
Pochettino diplomatically opted against offering any advice for Ten Hag amid reports the Dutchman has alienated members of his squad with his intense training regime and hardline approach to discipline.
Ten Hag denied the claims and Pochettino said: "I'm only a coach that tries to do my best. We are no one to give advice to my colleagues.
"It's not my duty to talk about what's going on in another place. I'm very respectful. I need to be respectful about another club."
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