There are some things that no Manchester United manager can allow, and losing to Manchester City and Liverpool in the space of four days is pretty high up that list of the forbidden. It will be some relief to David Moyes that he does not have to wake up this morning to find out how consecutive defeats to those two old enemies feels.
Beating Liverpool in the third round of the Capital One Cup will not solve all the problems that Moyes faces in pulling together the beginning of the post-Sir Alex Ferguson era, but it sure as hell gives him some room to breathe. In the days that followed the 4-1 defeat to City on Sunday, it must have felt suffocating at times for Moyes but, at last, he has his first significant scalp as United manager.
As the red smoke of the flares hung over Old Trafford, and Liverpool, who had some good periods in the game, threw everything at United in the closing stages, Moyes will have felt much of the tension and excitement that comes with this job. The edge of that technical area can be the loneliest of places, but when United are closing out a win it must feel like the job that he has worked for all his life.
At stake was a place, as it turned out, against Norwich City at home in the fourth round for the winner. The kind of prize that Ferguson, in those days when he used the competition as a proving ground for bright young academy players, might have been prepared to risk. Moyes needed to win.
There were times when he must have wondered. Brendan Rodgers picked arguably the best team he had at his disposal. On the other hand, Moyes, without the injured Robin Van Persie, chose a mix of first team regulars and fringe players like Luis Nani, Shinji Kagawa, Alexander Buttner and Jonny Evans. It was a risk but Javier Hernandez's goal just after half-time was enough for United.
For Rodgers, with Luis Suarez back in the side for the first time since the bite, this felt like an opportunity missed. Twice his side struck the frame of United's goal and they had the best of much of the first half but they could not push their advantage in those periods. And they let themselves down badly, Jose Enrique in particular, for United's goal.
It was not a pretty game at times and it was hard to pick an outstanding figure but Phil Jones' work in front of the back four was excellent and will have caught the eye of Roy Hodgson, in the directors' box. Also in there was Roy Keane, who became persona non grata after his acrimonious departure in 2005 but with Sir Alex Ferguson away in New York was deemed an acceptable presence.
The selection of Wayne Rooney as captain was one further step down the path of his rehabilitation as a United player. Not surprising, really. At the moment Moyes needs Rooney as much as any player apart from, perhaps, Van Persie. Given Liverpool's form going into the match, Moyes certainly needed his No 10 more than Rodgers needed Suarez, back from his suspension.
The debate over Rooney has been parked by the home fans at Old Trafford, perhaps forever. For much of the first half they seemed too consumed by the indifferent start to the Moyes era and that was reflected in the pensive quiet that consumed the home crowd early on. By the end, the atmosphere was much more raucous.
As for Moyes, the win gives his the best start of any United manager since Matt Busby took over in 1945. 'That's one of the good stats,“ said Moyes afterwards, ”because I haven't had many of those“.
United started brightly in the very first few minutes. There was a half a chance for Hernandez from a cross from the right and then Luis had a good shot deflected wide. But quickly that early momentum faded away from United and Liverpool looked the better side. What they failed to do was convert it into decent goalscoring chances.
Suarez's first action of significance came when he took too heavy a touch on a long ball from the left-back position from Enrique. It was flighted just right to drop over the head of Evans and it required a more delicate touch than the one provided by Suarez who ran it on too far and collided with David De Gea in pursuit.
Suarez is even further down the road of forgiveness with Liverpool fans after his summer of rebellion. The debate over his behaviour towards his own club seems to have ended even sooner than the one involving Rooney and United. He and Daniel Sturridge, playing just ahead of Victor Moses, offered more threat in the first half than Rooney and Hernandez who looked isolated early on.
As for the noise in the stadium before half-time, it came almost exclusively from the away support. They goaded Moyes and Rooney relentlessly and there was not much in the way of a defence put up by the home crowd who were simply seeking some reassurance from the players on the pitch. United rallied towards the end of the first half and took back some of the possession but there was very little to show for it in the way of chances.
There were staff and substitutes from both sides who had not even taken their seats when United scored in the first minute of the second half. Hernandez managed to lose Enrique with the simplest of deceptions - basic ally he refused to stay still. The United striker struck the ball on the volley beautifully, airborne when it reached him and then guiding it with his right foot past Simon Mignolet.
It flustered Liverpool who came at United immediately and allowed the home side to switch to a more counter-attacking style. Having been quiet in the first half, Kagawa - who was played out of position on the right - came into the game more. He is an unusual performer. His touch let him down badly at one point when he was running at goal but on 64 minutes he unleashed a fierce shot that touched the top of Mignolet's bar.
Kagawa might also have reasonably expected the ball back from Nani when United broke forward on 59 minutes. Hernandez brought the ball under control brilliantly and from there it went to Kagawa, to Nani and should have come back to the Japanese who was in a better position to shoot.
The hard work of Jones, and Evans and Chris Smalling in defence behind him, limited Suarez and Sturridge in that period. The Liverpool attackers created a sight of goal on 54 minutes when the ball popped out to Jordan Henderson but his shot was wide. They got closer. De Gea saved a point-blank header from Victor Moses. Then Suarez clipped the top of De Gea's bar with a free-kick.
Finally the game came alive. Rooney forced two fine saves out of Mignolet, the first from a free-kick, the next from a long-range shot. In the meantime, Moyes had brought on the 18-year-old Belgian, Adnan Zanuzaj, for Kagawa and Michael Carrick for Hernandez. In the final moments of pressure, Henderson struck De Gea's right post with a shot but United survived, and the relief was there in the roar that greeted the final whistle.
Manchester United (4-2-3-1)De Gea; R Da Silva, Evans, Smalling, Buttner; Jones, Giggs; Nani (Welbeck 90), Rooney, Kagawa (Januzaj 74); Hernandez (Carrick 74).
Liverpool (4-3-1-2): Mignolet; Toure, Skrtel, Sakho, Enrique; Henderson, Lucas (Kelly 64), Gerrard; Moses (Sterling 82); Sturridge, Suarez.
Man of the match: Jones.
Match rating: 7/10.
Referee M Clattenburg (Durham).