NOTTINGHAM, England -- Mark Robins is etched in Manchester United history as the player who saved Sir Alex Ferguson's managerial job with an FA Cup winner at Nottingham Forest nearly 35 years ago. Erik ten Hag can only hope that Casemiro is famous for the same reason in another 35 years' time.

Casemiro's glancing header at the near post in the 89th minute on Wednesday earned Man United a 1-0 win over Forest in the FA Cup fifth round, easing the pressure on his under-fire manager, Ten Hag.

After Robins' goal at the City Ground in January 1990, United went on to win the FA Cup to kickstart an unprecedented era of success under Ferguson at Old Trafford. There's work to do if Ten Hag's story is going to follow a similar storyline -- particularly with Liverpool waiting in the quarterfinals -- but at the very least it's a much-needed win at the start of what could be a defining week for the Dutchman.

Next up is a visit to Manchester City on Sunday, a derby fixture that would've made the spotlight on Ten Hag that much harsher had United seen their only chance for hardware vanish after an FA Cup exit. For now, though, thanks to Wednesday's victory, Ten Hag can breathe again.

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"It's big," said Ten Hag. "We want to win every competition, so every game is big. The fans, they deserve a team who are fighting and that show domination and passion and desire and resilience and they showed it today.

"There are many good teams in the Premier League and Liverpool and [Manchester] City are top, but it's a great challenge and we're really looking forward to [playing Liverpool in the next round] because we like the challenge."

As Ferguson found out all those years ago, management can sometimes be about timing, and there's no doubt that Ten Hag needed this now.

The defeat to Fulham on Saturday was a miserable example of everything that has been wrong at United this season, and even though many of the same flaws were on show against Forest, United found a way to win.

"We created good chances but we allowed them some counters and then after that we took control and we were more calm and composed," Ten Hag said. "I'm very pleased with the second half and very pleased with the spirit and passion and desire they showed, which is always the standard."

Forest, who beat United here in December, will wonder how they managed to have 16 shots but couldn't score while United, who had 20 of their own, will feel the game should have been put to bed long before Casemiro stooped to nudge in Bruno Fernandes' free kick from the left.

"I'm disappointed for the fans," said Forest manager Nuno Espirito Santo. "We had good situations and we're disappointed to lose at the end."

The importance of the goal wasn't lost on Casemiro who roared and fist-pumped in front of the 6,000 fans who made the two-hour trip from Manchester. After five minutes of stoppage time, the United supporters began to sing their Casemiro chant and the 32-year-old saluted and beat his chest with his fist.

Of all the issues Ten Hag has faced this season, Casemiro's commitment to the cause isn't one of them. Ten Hag will need all of Casemiro's quality and experience at the Etihad this weekend.

"He's a fantastic player," Ten Hag said. "He's scored so many goals for us, more than he has in his career. It's great to have a player like Casemiro in your team and you see how important he is for us and when he's not there you really miss him. His leadership makes us play better and the quality he has on the ball."

Speaking on Tuesday, Ten Hag said he doesn't care about the noise around his job -- but without a public guarantee from new part-owner Sir Jim Ratcliffe, the speculation will continue.

As disappointing as this season has been, United can still turn it around by winning the FA Cup and qualifying for the Champions League.

Given the financial boost generated by qualifying for Europe's top club competition, it could be that Ten Hag's future is tied to finishing in the top four of the Premier League, but reaching Wembley and winning a second trophy as United boss would also go a long way towards convincing Ratcliffe and securing his position ahead of next season.

The 1990 FA Cup was Ferguson's first trophy at Old Trafford and came at a time when there were mounting questions about whether or not the Scotsman should be sacked. It was Robins' goal in a 1-0 win at the City Ground in the third round that gave United and Ferguson the chance to reach Wembley.

Ten Hag is still alive in this season's FA Cup and thanks to Casemiro's Robins moment there might be life left in his reign as United coach