Although the Saints had a man sent off inside two minutes, Manchester United capitalised on the opportunity and saw off Ralph Hassenhuttl's side with intent. Here's what we learned.
Goals return to Manchester United
Having mustered a meagre six goals in six league games throughout January, there was the slow growth of concern that Solskjaer's offensive machine might be beginning to stutter.
Granted, an early red card for Alex Jankewitz significantly shifted the tide in United's favour. However, they have shown time and time again to be unable to unlock defences which close up shop, meaning the game's new complexion presented a wholly different challenge to an aggressive Southampton.
Solskjaer made note of this in his post-match comments and will be buoyed by his team showing enough of a killer edge to have seven different goalscorers (and an own goal) while keeping a clean sheet.
Aaron Wan-Bissaka showed intent to develop
When Luke Shaw whipped in a deep cross from the left side, few would've expected to see Wan-Bissaka barrelling in to connect with it, neatly guiding the ball across the goal to nestle near the opposite post for his second career goal.
That was the story of the night for Wan-Bissaka, who continually found space down the flank and made a series of encouraging burst forward to support. He forewent his predictable shimmy then dart right and actually put crosses in, eventually chalking up an assist for Anthony Martial. It was refreshing to see Wan-Bissaka look comfortable in a more offensive role, and hopefully, this is a turning point for him.
Mason Greenwood staked his claim for the right
Few players may have been as happy with the starting lineup as Mason Greenwood, who has seen Premier League opportunities somewhat limited this season, with ten starts prior to the game.
The academy starlet took his opportunity and was scintillating around the pitch, merciless in his runs forward and a reliable presence to bolster side wherever needed. He may have 'only' got the one assist in return, but he led United in dribbles and was behind Fernandes only in key passes and shots on target.
Still without a genuine right-wing, at least until Amad Diallo makes his way to the first team, Greenwood is the only player who looks comfortable there and proved it once again.
Martial and Cavani are helping each other
It's easy to pick up on the difficulties being experienced by Martial, especially given his 17 league goals last year. He's struggled this campaign but has already netted four, matching his league tally from 2016/17 and five off of his 2017/18 total.
Last night was exactly the performance the Frenchman needed, but not just for him. The presence of Edinson Cavani is providing genuine competition for Martial's starting berth, as shown yesterday. With both forwards full of energy and getting on the scoresheet, it's precisely this squad competition Solskjaer needs to win titles.
More questionable substitutions by Solskjaer
Although it was a night of glory and reinvigoration for United, Solskjaer once again provided material for his critics with his substitutions. By the time an hour had passed, all three changes had been rung, with Donny van de Beek, Martial, and Daniel James taking the places of Shaw, Cavani and Rashford respectively.
With Cavani understandably off as an injury concern, Solskjaer had two subs to play with. It seemed ill-advised to let Fernandes play a full 90 with Everton on the weekend, and it was a big risk to not replace Shaw with Alex Telles, despite the commendable performance of van de Beek.
It was a night of highs for Manchester United, who needed an emphatic performance to get back on track with their title push.