They returned to the top of the Premier League for the first time in a long time, were knocked off briefly by arch-rivals Manchester City on Saturday and, full of confidence, strode out onto the turf at the Emirates Stadium 24 hours later looking to re-assert themselves.
Instead, Manchester United were swept away well before half-time by an exhilarating Arsenal, who were 3-0 up in 20 minutes as they tore through Louis van Gaal's men with searing pace, slick movement and wonderful trickery.
With tough matches looming next - away ties against Everton and CSKA Moscow, and a Manchester Derby against City at Old Trafford - many believe United's season will fall apart after the international break, following the manner in which they were so badly exposed by the Gunners.
Lee Sharpe disagrees. In fact, he believes United will bounce back and continue to challenge for the title.
The former Red Devil believes United will be galvanised by their humiliating defeat at the Emirates Stadium, despite having an unbalanced squad and a counter-intuitive game plan, given the players at Louis van Gaal's disposal.
"What that defeat will do is ensure there won't be any complacency," said the 44-year-old former winger, on the sidelines of The Castlewood Group Battle of the Reds press conference at the Singapore Marriott Tang Plaza Hotel yesterday.
Sharpe and Liverpool legend Robbie Fowler will play in the match between the United Masters and the Liverpool Masters at the National Stadium on Nov 14.
"They have sat at the top of the league this season, but they haven't beaten people convincingly... And the Arsenal game just highlighted the problems," the former England international said.
"The Everton game is next, after a week's break, and they have to come out and play at 100kmh.
"United have to come out of the blocks really quick and not allow Everton any chance to settle and do to Everton what Arsenal did to them."
With Rio Ferdinand and Nemanja Vidic a memory, Sharpe was surprised that United did not sign a centre back before the season started, given the departure of Jonny Evans.
CENTRE BACK NEEDED
He expects van Gaal to sign one in the January transfer window.
The signing of a top central defender, along with van Gaal adopting a more attacking strategy, will make United title challengers this season, according to Sharpe.
"I suppose in order to improve on last year, they'll need to challenge for the title this year," he said.
"They are capable of challenging if they buy a defender... But if you looked down the years, the teams that have won the Premier League have generally counter-attacked with pace.
"He (van Gaal) has the players - quick wide men, people who get into the box from midfield and people who hold their own up front.
"If the manager can play a quicker game, it would suit (Memphis Depay and Anthony Martial). Right now it stifles them a bit playing 'tappy', sideways football."
Dutchman van Gaal's methods have polarised opinions among fans and ex-players, including Sharpe.
"There's a fine line between genius and madness, and I am not too sure which side of the line he is at the moment," said the 1.83m-tall former attacker, who scored 21 times in 193 appearances for United.
"Sometimes I think he's brilliant, and sometimes I think he's absolutely crazy."
This article was first published on October 7, 2015.
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