Manchester United got their spluttering season back on track with a 2-0 win against Arsenal in the FA Cup quarter-finals at Old Trafford on Saturday.
Sir Alex Ferguson's side had lost three of their last five Premier League matches, but goals from Fabio da Silva and Wayne Rooney restored the feel-good factor and booked a place in the Wembley semi-finals.
While United's morale will have been lifted by victory against a major rival, Arsenal's campaign is in danger of imploding.
The Gunners now have only the Premier League title to aim for after a miserable two weeks which has seen them lose the League Cup final to Birmingham and crash out of the Champions League and FA Cup.
United goalkeeper Edwin van der Sar admitted it was important for his team to get back to winning ways.
"We got our goals, luckily I pulled off a couple of saves and we defended well," he said.
"It was important of course because we lost to Chelsea and Liverpool so the gap in the league is now non-existent. We needed to win tonight for another chance of silverware."
The 40-year-old has already announced his intention to retire at the end of the season and, asked if he is tempted to change his mind, he insisted: "No, definitely not."
Arsenal boss Arsene Wenger confirmed Swiss defender Johan Djourou will be out for the rest of the season after being stretchered off with a dislocated shoulder.
Wenger added: "I cannot fault our effort but things are not going our way at the moment.
"United were much more clinical, we have had a very difficult week. The team will recover from that and refocus."
Ferguson sent out a slightly weakened team which included seven defenders as he rested players ahead of Tuesday's Champions League second leg against Marseille, while Wenger played his strongest available eleven. It was Ferguson's selection gamble that paid off.
Fabio opened the scoring with a close-range finish in the 28th minute after Manuel Almunia could only push Javier Hernandez's header from a Rooney cross into the Brazilian's path.
Arsenal's Robin van Persie, controversially sent off for kicking the ball away against Barcelona in midweek, almost equalised before the break but the Dutch forward saw his low shot turned away by Van der Sar.
Laurent Koscielny was denied by van der Sar soon after half-time and United, who last won the Cup in 2004, took advantage of that escape to put the tie beyond Arsenal's reach in the 49th minute.
Rafael da Silva's surging run and cross forced Johan Djourou into a block that looped the ball towards Rooney and the England striker headed past Almunia from a tight angle.
In the day's other quarter-final, Lee Chung-Yong fired Bolton into the FA Cup last four as the South Korean's late goal clinched a 3-2 win over Birmingham at St Andrew's.
Owen Coyle's side looked to have been denied a place in the last four when Kevin Phillips hit a late equaliser for Birmingham, but Bolton midfielder Lee headed the winner in the 90th minute to send the visitors to the Wembley semis.
Bolton had taken the lead through Johan Elmander's cool finish in the 21st minute before Cameron Jerome lashed in Birmingham's first equaliser in the 38th minute.
Kevin Davies converted a 66th-minute penalty, awarded after Curtis Davies fouled the Bolton striker, only for Phillips to scoop in a superb equaliser with 10 minutes to play.
But Birmingham's dreams of adding the FA Cup to the League Cup they won against Arsenal last month came to an end when substitute Lee ran onto Davies's header and nodded past Ben Foster.
Coyle saluted Lee's influential display but admitted he will continue to rotate the winger in and out of the side to keep him fresh.
"I think Lee is capable of playing for any team. But he hasn't had a break for two years though and we have to be careful with him," Coyle said."
Sunday's two quarter-finals see Manchester City host Championship club Reading, while West Ham travel to Stoke.