The Red Devils capped off a positive week with a 3-2 victory over Arsenal in the Premier League on Sunday afternoon to give their hopes of finishing in the top four a significant boost.
That win over the Gunners at Old Trafford left United three points behind fourth-placed Manchester City, who have a game in hand, heading into the final 11 games of the season.
United have struggled to string together a series of positive results all season and still face an uphill struggle to secure qualification for next season’s Champions League.
And Lawrenson feels that Watford could have too much for an injury-hit United side at Old Trafford on Wednesday night.
Writing in his column for BBC Sport, Lawrenson said: “The goals have started flowing for Manchester United again, and they have 11 in their last three games – although eight of them were against Shrewsbury and FC Midtjylland.
“I think Watford will be a tougher nut to crack defensively and they will also look to hit United on the break, so they will cause Louis van Gaal’s side some problems.”
United will take on Liverpool in the last 16 of the Europa League next month.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news