If David Moyes didn't know it in September, then he certainly does now.
Manchester United do not have a strong enough squad to win the Premier League title.
Chelsea, Manchester City, Arsenal and Liverpool all strengthened over the summer months, while Moyes only managed to bring Marouane Fellaini to United after taking the reins from Sir Alex Ferguson.
And the Red Devils' lack of success in the summer transfer market has contributed towards their dreadful start to the 2013/14 Premier League campaign.
United are ninth in the table, 13 points off league-leaders Arsenal. With no realistic chance of retaining their title, Moyes must ensure that his side secure a top-four finish. Anything less would be an unmitigated disaster for both him and the club.
After achieving that, Moyes must work on securing at least four players in time for the 2014/15 campaign. Buying in January can often prove troublesome, so the United boss could be forgiven for waiting until the season's out before spending the club's cash on new recruits.
Moyes knows that the priority has to be signing a new central midfielder. Fellaini is still settling into the club, Michael Carrick isn't getting any younger, while Tom Cleverley and Anderson simply aren't up to the job.
In order to complete with the best, United must be looking to buy the best, and a player like Koke from Atletico Madrid or Ilkay Gundogan from Borussia Dortmund would be ideal.
Next on the list is a new left-back. Moyes, to his credit, identified this as a problem position before the summer transfer window closed, hence his desire to sign either Leighton Baines from Everton or Fabio Coentrao on a season-long from Real Madrid.
Patrice Evra, United's current left-back, is in the early stages of decline - and United should be looking to sign someone like Coentrao or Luke Shaw from Southampton as a long-term replacement.
The Red Devils could also do with a new left-winger. Ashley Young isn't United class, Shinji Kagawa isn't a left-winger and neither is Danny Welbeck.
Someone like Angel Di Maria from Real Madrid would be perfect. The Argentina international has played a peripheral role at the Bernabeu of late, but he would be a genuine star at Old Trafford.
And, finally, Moyes must consider bringing in a new striker.
Robin van Persie will be 31 next season, while doubts persist over Javier Hernandez's ability to affect a game when he starts.
Borussia Dortmund's Robert Lewandowski would be the ideal signing, but he looks poised to join Bayern Munich.
Still, if Moyes doesn't ask, he doesn't get.
And if he doesn't get any of his targets, next season could be his last at Old Trafford.