With 15 games of the Premier League season remaining ahead of Sunday`s trip to West Ham United, Manchester United know that the time for experimentation is at an end.
United went into the weekend in third place in the table, but their rivals for Champions League qualification all appear to be finding form and Louis van Gaal`s side continue to impress only in fits and starts.
After a run of only one win in five league games, culminating in a 1-0 loss at home to Southampton, United have got back on track, winning their last two games and scoring six goals in the process.
But both of those victories came with caveats. Leicester City, who United beat 3-1 last weekend, are bottom of the table, and Cambridge United, beaten 3-0 in the FA Cup on Tuesday, play in the fourth tier.
Double-edged statistics become a recurring theme when United`s recent form is subjected to scrutiny.
Van Gaal`s side have not lost away from home since a 1-0 reverse at Manchester City on November 2, but in their last four away matches they have won only once, and that at second-bottom Queens Park Rangers.
And while last weekend`s results enabled United to hold on to third place and close to within five points of second-placed Manchester City, the teams below them -- Arsenal, Tottenham Hotspur and Liverpool -- seem to be slipping into gear.
Van Gaal`s tactical experimentations mean that United still have the look of a work in progress and in West Ham, they face opponents who have lost only once in their last 10 home matches.
"I said before the game against Leicester City that this is an important week and we have to win all three matches," said Van Gaal, who has vowed to contest a Football Association charge over remarks he made about the referee following last month`s 0-0 draw at Cambridge.
"After we beat Leicester, we were third in the league. After that, we beat Cambridge and we are in the next round of the FA Cup.
"Now, we have to continue and all of the players know that it`s true, but it`s not so easy because we have to play away in London against West Ham and it was a tough game in Manchester.
"It shall not be easy, but we want to continue. We have to win in London."United can at least call on a close to fully fit squad, with Michael Carrick (calf) the only doubt for the trip to Upton Park, where they won 2-0 last season in a game that saw Wayne Rooney score an outrageous lob from the halfway line.
Rooney was sent off in this season`s reverse fixture for hacking down Stewart Downing after opening the scoring in a 2-1 win.
West Ham`s infirmary, in stark contrast, is full to bursting, with hamstring injuries to Winston Reid and James Collins likely to see Cheikhou Kouyate pressed into action as an emergency centre-back.
Record signing Andy Carroll, meanwhile, is a doubt after injuring his ankle during the 2-0 loss at his former club Liverpool last weekend.
"I`ve had to bring a list of the injuries with me," West Ham manager Sam Allardyce told his pre-match press conference.
"James Collins, Winston Reid, Guy Demel, Diego Poyet, Doneil Henry and Andy Carroll lie in our medical room at the moment.
"We`re not sure how many of those will make it for Sunday. With such a big week coming -- three games in a week -- there`ll be very few risks taken, unless they`re 100 percent fit."
The injury blight has contributed to a return of only two wins from eight league matches -- against bottom-three sides Leicester and Hull City -- which has seen West Ham slide to eighth place in the table.
But they have shown themselves capable of rising to the occasion on home soil this term, notably beating Liverpool and Manchester City.