John Flynn, the assistant referee, ignored the golden rule of an flag-bearer when officiating at Old Trafford; if in doubt, keep your flag down.
Premier League: Best & worst
Worst decision - John Flynn
Sir Alex Ferguson needs little opportunity to use a decision by an official to mask the failings of his team but, for once, the fiery Scot had a point on Saturday.
In penalising Rio Ferdinand for a wonderfully-timed tackle on Hatem Ben Arfa - a tackle that was reminiscent of Ferdinand's impeccable reading of the game at the 2002 World Cup - Flynn, the assistant referee, ignored the golden rule of an flag-bearer when officiating at Old Trafford; if in doubt, keep your flag down.
It prevents you from incurring the wrath of Ferguson, the partisan crowd and being intimidated by the haranguing of the Manchester United players.
Flynn got it wrong, so wrong and, for a minute, the Flight Sergeant could have been forgiven for thinking serving as a Weapon Systems Operator in Iraq and Afghanistan would have been less fraught.
Best officiating - Lee Probert
The official made the call of the weekend and possibly the season by showing a yellow card to Youssuf Mulumbu.
Nobody likes to see anyone shown a card - except when it is branded to a player who waves an imaginary card to a referee in a desperate attempt to get another player cautioned.
Mulumbu was aware Sandro, the Tottenham Hotspur midfielder, who was showing signs of rustiness in a rare start, had already been cautioned when he fouled him towards the end of the first half.
Sensing his team gaining a numerical advantage if the Brazilian was sent off, Mulumbu leapt to his feet and started gesticulating for Sandro to be sent off in a manner normally reserved for the pitches of Spain and Italy. But Probert was having none of it and in cautioning Mulumbu, sent out the most welcome of messages.
Worst anticipation - Jerome Thomas
Some West Bromwich Albion fans felt it necessary to abuse Paul Robinson, their former left-back, when he returned to The Hawthorns last week in the colours of Bolton Wanderers.
Robinson played more than 200 games in six years at West Brom and made the club a profit of £625,000 (Dh3.5million) when he left for Bolton.
Robinson is one of the most committed and honest professionals in the league, certainly more committed than Thomas, who stood motionless and watched Emmanuel Adebayor run up and take a penalty against Ben Foster, his teammate, with his hands on hips.
He did not move, not even an inch as the spot-kick was saved and rebounded into the path of Adebayor. Thomas may not have prevented Adebayor tucking in the rebound but he could at least have strained a sinew in attempting to.
Best selection - Andre Villas-Boas
Well, perhaps picking Oriel Romeu was not the "best selection" but certainly the most long overdue.
Amid the significant summer spending by Liverpool and the Manchester clubs, the arrival of Romeu from Barcelona slipped under the radar.
The latest midfield technician to emerge from the Barcelona youth system, Romeu has had to be patient while Andre Villas-Boas persisted with John Obi Mikel as Chelsea's deep-lying midfielder.
But Mikel's mistake against Liverpool last week prompted a much-needed change at the base of Chelsea's midfield and Romeu took his chance, producing the kind of efficient and polished display against Wolverhampton Wanderers that showed why Barcelona have a buy-back option for the first two seasons.
Worst tackle - Alan Hutton
The Scottish defender is emerging as a weekly contender for this award.
Just over a month after a tackle on Shane Long that was, according to Roy Hodgson, the West Brom head coach, lucky not to leave the striker with "two broken legs", Hutton was reckless again yesterday.
Neil Taylor, the Swansea City left-back, was the recipient of a bone-crunching, reckless tackle this time, just 19 minutes after the crowd and players united in a round of applause to mark the tragic death of Gary Speed.
Hutton's timing was therefore wrong on two counts and having spent eight months on the sidelines in 2005 with a broken leg while playing for Glasgow Rangers, you would thought he would think twice before making potentially career-threatening tackles.