Despite United riding high in the Premier League, their defenders have been criticised for a patchy start to the season and again performed in shaky fashion in the FA Cup on Saturday.
Joe Cole twice set up headed goals from James Collins as the Hammers closed in on third-round glory, only for Robin Van Persie to break their hearts with a stoppage time equaliser in an entertaining 2-2 draw.
"We always know that on set-pieces they are a tough team to play against and
eventually they scored two against us from crosses," said Vidic who has only just returned to first-team action after a long-term knee injury.
"They scored from the second ball which we should look at again, and we are definitely a bit disappointed. It is something to talk about.
"We have the height in the team, we should deal better with that, but most important is that we managed to stay in the game."
Vidic insisted that despite bigger prizes on offer for United this season, the FA Cup remained a top priority.
"We did not win the trophy for the last eight years and it's a trophy we are looking to win," he added.
"We showed that in how we celebrated the goal, and I am hoping at home it will be a different game."
United's replay with the Hammers will take place on 16th January, just after the home league game with Liverpool and ahead of a testing trip to Tottenham.
Manager Sir Alex Ferguson is hoping his injury list will ease, allowing a return to an efficient rotation policy - particularly with the Champions League set to resume in February.
"I have got a good strong squad and I am sure players will all be back by the time we play all these games," said Ferguson.
"Nani has started training as is almost fit now, Phil Jones should be ready in
the next week or so. We have a strong squad, so why don't we use it?"
Regarding striker Van Persie, Vidic was full of praise for the coolness of the late finish that ensured his side were in the hat for the fourth round draw.
"His touch is magnificent and his finishing is top class," the Serbian told MUTV. "It is movement from the book, touch from the book, goal from the book.
"It is something they can show to kids, how to move and finish in the last third. He was magnificent for us, we just hope he is going to be in the same
form in the end."