United are on the verge of a place in the knockout stages of the Champions League for the first time in four years.
The Reds 2-0 win over Benfica - who have lost all their games and scored only once - saw the Reds make it four wins from four, and 12 points from 12, in Group A.
CSKA Moscow won 2-1 in Switzerland against Basel in the other game, leaving United six points clear but still waiting to go through.
United need a solitary point from our last two fixtures - away to the Swiss champions and at home to CSKA - to mathematically confirm our place in the last 16.
This is only the fourth time that we've boasted a 100% record after the first four Champions League ties - having done so in 1997/98, 2002/03, 2007/08 (when we won it), and 2012/13.
In the latter of those campaigns, the Reds were knocked out of the competition at the last 16 stage, in contentious circumstances against Real Madrid.
With United on course for a famous win and a place in the last eight, Nani's controversial sending off swung the tie in favour of the Spanish giants - managed by a certain Jose Mourinho.
The following season under David Moyes, United came back from 2-0 down to edge past Olympiakos before a quarter-final KO at the hands of the holders Bayern.
Then came was the ignominious early exit from one of the competition's easiest groups in the 2015-16 campaign under Louis van Gaal.
United were demoted into the Europa League after a third placed finish in a section that also included Wolfsburg, PSV and CSKA again (what is it about them, us and the Champions League).
Although this was from a vintage performance against the Portuguese champions and the group's top seeds, it was another solid result.
The Reds have only conceded a single goal in the competition so far - and that came in the 4-1 win in Moscow - and United have been tipped to make an impact at the latter stages.
A watertight defence will certainly help, and David de Gea again underlined his importance with two brilliant saves, one in each half, to secure an eleventh clean sheet in 15 games.
The Reds are showing all the hallmarks of a classic Jose side: a miserly backline the ability to grind out results and an imposing record at home.
Old Trafford looks to be the fortress it was once famed to be - this was a 37th match unbeaten at home for United in all competitions, stretching back to September last year.