Alex Ferguson fears Manchester United will struggle to break down Middlesbrough today because of the work his former assistant Steve McClaren has carried out at the Riverside stadium.
McClaren, who helped United win the European Cup in 1999, left Old Trafford in June 2001 to become Boro manager and has impressed many by transforming the north-east club's fortunes.
"Steve has improved them this season," Ferguson told reporters on Tuesday.
"He has bought two or three players in who have made a massive difference. (Italian striker) Massimo Maccarrone, (Cameroon midfielder) Geremi, and (Australian) Luke Wilkshire have done well and there is a massive improvement from last year.
"Steve has based everything on organisation. He has brought in (Ugo) Ehiogu and (Gareth) Southgate, who are both familiar with each other's play after a long time with Aston Villa.
"That is the kind of organisation we will have to break down."
With Argentine Juan Sebastian Veron struggling to be fit again, Ferguson could give club captain Roy Keane a full 90 minutes in
The Irish midfielder returned from more than three months out with a hip injury as a second-half substitute in United's 1-0 defeat to Blackburn Rovers on Sunday.
UNITED BOOST
"It was a boost to have Roy back on Sunday but he was not 100 percent," said Ferguson.
"He had only had one reserve game after being out for nearly four months and he needs plenty (more) games.
"The half hour (against Blackburn) will help him but now we have to decide the next best way to use him. He is phenomenal.
"The (reaction of the) supporters told you everything...he inspires people roundabout him."
United, in third place, trail leaders Arsenal by four points at the top of the English premier league table, but Ferguson still believes his side can lift the title.
"We have done well to recapture our position at the top," he said.
"Sunday was a disappointment but we have put ourselves in with a chance. That is important. We know we have the resilience and stamina to make a good challenge in the second half of the season."
