Scott Taylor's goal inflicted on the second defeat of the season on the Wearsiders and with Ipswich beating Portsmouth 3-0, Sunderland's lead at the top of the First Division is now down to five points.
They host Crewe today with the bottom club on a high after only their fourth victory in 25 games - a 3-1 win against Bury. Reid said: "You can't expect to win every match and possibly it's the kick up the backside we needed.
"I warned the players before the match that with such a bad home record, Tranmere were sure to put up a tremendous battle because they're a good team, and unfortunately I was right."
Dario Gradi, the Crewe manager, said: "We'll go up there to enjoy ourselves as we're not expected to do anything.
"In fact, there will be more pressure on them because their fans will believe they should beat us quite easily and if they get frustrated we may be able to sneak something."
Portsmouth's troubles were extended on the field as their loss to Ipswich on Saturday made it three defeats in a row and they are just one place and one point above Oxford, who are in the relegation zone.
Alan Ball was furious with their display and their manager said: "What words do I use? Pathetic, abysmal, gutless and disgraceful all come to mind. We let down our supporters in every aspect of our play.
"Ipswich are a good pass-and-move team but we were absolutely embarrassing apart from the keeper. If my footballers were bricklayers, the house they built would fall down."
Second-placed Ipswich visit Wolves today with Kieron Dyer expected to play despite picking up a knock on the calf.
Watford lie third, five points behind Ipswich, following their 1-0 defeat of Bristol City - a game which saw the Hornets manager, Graham Taylor, return to the touchline for the first time since his illness.
Bristol City are one place off the bottom of the table and today they face a derby at Ashton Gate with Swindon, who added to Wolves' woes with a late Iffy Onuora goal to seal a 1-0 win on Saturday.
George Ndah will have a fitness test on a hamstring injury for Swindon, who are unlikely to risk Ty Gooden even though he has recovered from a groin problem.
Birmingham are fourth after beating Sheffield United 1-0 thanks to Paul Furlong's penalty and they look set to field an unchanged side at Bury. Trevor Francis, their manager, said: "I'm looking for the same display against Bury that we produced against Sheffield United.
"I can't believe that we only beat United 1-0 as it was a performance that merited a three or four-goal win."
Bolton and Bradford City played out a goalless draw at the Reebok Stadium and the Bolton manager, Colin Todd, is looking for his side to make up ground on the leaders with victory at Port Vale.
"You're always disappointed when you don't take maximum points," he said. "It's points dropped but we hope to come back on Monday."
John Hendrie is demanding more examples of the display his Barnsley side gave in their 1-0 defeat of Stockport. Arjan de Zeeuw's goal sealed the three points and Hendrie, whose team host Queen's Park Rangers today, said: "It wasn't a pretty game to watch - in fact it was terrible - but the main thing is we came away with the victory and a clean sheet. Now we've got to maintain that attitude in all our future games."
Huddersfield kept up their unexpected promotion push with a 2-0 defeat of Grimsby and they complete their festive programme of fixtures with a derby at Sheffield United.
West Bromwich's up-and-down season continued with a 3-2 victory at home to Port Vale and the Baggies' game today is at Crystal Palace, who beat Oxford 3-1 at the Manor Ground.Reuse content