Ole Gunnar Solskjaer's side travel to the south coast on Saturday for a Premier League lunch time kick off, for our second game - and first away day - of the new season. We also know now that the two combatants will be sparring again in double quick time, with Graham Potter's side setting up a fourth round Carabao Cup clash for next week after their 2-0 win at Preston in midweek.
The last time such an occurrence happened was when Sir Alex Ferguson was still in charge at Old Trafford, back in 2012. United faced Chelsea at Stamford Bridge twice in the space of four days, with the two matches again coming in the league and the League Cup. Ferguson - as Solskjaer will probably do - picked two very different line ups for each game, with the Reds winning the first tie 3-2 in the league game on the Sunday. Javier Hernandez hit a late winner after leaders Chelsea had hit back from 2-0 down through a certain Juan Mata and Ramires, after a David Luiz own goal and a Robin van Persie strike had put the Reds in control. Chelsea, in the final throes of Roberto Di Matteo's tenure, ended the game with nine men after red cards for Branislav Ivanovic and Fernando Torres.
Just over 72 hours later, a rotated Reds side took on the Blues again, and Sir Alex made ten changes with only Rafael keeping his place from the league game. Scott Wootton and Michael Keane, now of Everton, played at centre-back.
In a ridiculously rip roaring and see-sawing contest, United took the lead on three separate occasions, through Ryan Giggs, Hernandez again (so often the scourge of Chelsea) and Nani, only for inexperience to show. Pegged back each time, Luiz, Gary Cahill and a late Eden Hazard penalty meant the Reds had to settle for extra-time. The Blues bench power eventually shone through, with Daniel Sturridge and Ramires again finding the net in the additional 30 minutes. A late Giggs penalty wasn't enough to prevent an extraordinary 4-5 defeat for United. The Reds of United and the Blues of Chelsea met five times that season with Chelsea winning three, one draw and that five-goal thriller in favour of us mentioned above.
Before that, you have to go all the way back to the triumphant 1967/68 campaign, under another knight of the realm, for another example of back to back away deja vu.
Sir Matt Busby's United side - they would go on to win the European Cup that season - went down 1-0 to Spurs in midweek at White Hart Lane, hot on the heels of a 2-1 victory on the same ground (Bobby Charlton notched the winner), the previous Saturday.
United faced West Ham United in 2016 twice in the space of three days at Old Trafford.
So it has happened but its rare and this will be only the third occasion that United have played the same opponents away from home on the same ground in successive ties.