On a day when Donny van de Beek hoped to show why he deserves more minutes for Manchester United, up stepped Bruno Fernandes to show why that simply isn't happening.

The eye-catching selection of Van de Beek ahead of Fernandes for this FA Cup clash of giants at Old Trafford was all about "rotation", according to Ole Gunnar Solskjaer.

United's manager clearly felt his team could combat a faltering Liverpool team without their star man, albeit leaving him on the bench in case of emergency.

"Donny needs to be playing games as well and it's a big game for Donny to come into," Solskjaer told the BBC.

Van de Beek has not started a Premier League game since he was hauled off with United trailing at half-time at West Ham in early December, and he might not be starting any soon either given how this game transpired.

A 66th-minute switch of the Portuguese for the underwhelming Van de Beek proved pivotal, and the delightful free-kick from Fernandes that settled an absorbing game 3-2 in United's favour was one that had been conceived on Saturday.

"I think he stayed about 45 minutes after training yesterday shooting free-kicks, so I was quite confident that he was going to hit the target," Solskjaer said.

Solskjaer, the erstwhile supersub, knew the calibre of replacement that was up his sleeve, and the rotation worked in a roundabout way. Are we looking at more proof that United's once-maligned Norwegian boss is actually a tactical master?

Liverpool's season, meanwhile, takes another negative turn.

Donny fluffs his big chance

With a mere 18 passes and 23 touches, Van de Beek was peripheral in a midfield where Paul Pogba shone and Scott McTominay fought for every ball.

The former Ajax man had a glorious early chance to stamp his mark on the game when he burst into space on the right and looked sure to dart towards the penalty area, as Edinson Cavani waited for a pass in the centre.

But no. Van de Beek paused and decided to go backwards, and the chance was gone.

This game was a world away from the Anfield snore draw seven days previously in the Premier League, yet Van de Beek largely let it pass him by.

By the time Fernandes cracked his sublime winner into the right corner, Van de Beek must have been wondering when such an opportunity will arise again.

Salah shows he must start

Like Fernandes, Salah has seen his form and contribution questioned in recent weeks, and just as United's match-winner dispelled such criticism, so did Liverpool's main man.

After all the talk about front threes, and which of these sides had the most deadly attacking trio, Liverpool boss Jurgen Klopp went with a two-man strikeforce, Salah and Roberto Firmino linking up and Sadio Mane on the bench.

Both Salah and Firmino had been substitutes on Thursday for the defeat to Burnley, but they were a combination that United struggled to contain at times here.

Salah struck twice, the first a sublime chip, and Firmino set up both. The Brazilian has now assisted Salah for 18 goals during their time together at Liverpool, the most any player has set up another during Klopp's reign.

Unlike Firmino and Mane, Salah has exceeded his expected goals (xG) in the Premier League this season, with eight non-penalty goals from an xG of 5.3, and if Liverpool are to resurrect their season, the bench is surely no place for the Egyptian.

Glorious Greenwood

Mason Greenwood has not scored in the Premier League since that West Ham game, when he helped United turn their half-time deficit around and earn a 3-1 victory.

Here he looked lively from the early stages, albeit with one too many lollipops and insufficient tasty final product until he cancelled out Salah's opener.

The way the 19-year-old ended an 10-game barren spell spoke volumes of his belief, with Marcus Rashford's sweeping pass over the Liverpool defence finding his wing twin on the right and allowing Greenwood to thump a low shot past Alisson.

With Rashford also on target, this was quite a day to savour for the hosts.