It will take a bit more time to determine whether Manchester United's recent improvement is more down to Mourinho's exit or Ole Gunnar Solskjaer's own good work, but there has been a tangible change in the atmosphere at Old Trafford since the switch was made.
United scored three or more goals on just two occasions in Mourinho's final 23 league games at the helm, but they have managed it in both matches of Solskjaer's tenure so far, hitting eight goals and conceding just twice in that time.
Cynics will point out that tougher tests are to come for United, whose wins have come against Cardiff City and Huddersfield Town, the latter of which saw Paul Pogba - so often criticised for playing below his potential under Mourinho - score twice in a 3-1 triumph.
Questions must be asked of the players considering how quickly they have upped their game in the wake of Mourinho's dismissal, although it also speaks volumes for how restricted they must have felt under the previous boss.
Simply being afforded more attacking freedom appears to have given many of the players a new lease of life, although there is still work to do defensively with United having kept just two clean sheets throughout the opening half of the season.
Indeed, United have conceded 31 goals already this term - more than in the entire 2016-17 and 2017-18 campaigns - and it is the first time they have shipped more than 30 goals after 19 games of a top-flight season since 1962-63.
Solskjaer's side have so far outscored opposition in his fledgling reign, and if they manage that again on Sunday then he would become only the third manager in the club's history to win his first three league games at the helm - after Matt Busby and Mourinho himself.
It would provide a positive end to a turbulent year, and 2019 promises to be another big one for the club with one major decision - the next permanent manager - already on the horizon.
It is a job some of the biggest names in football are understood to be keen on, although a failure to secure Champions League football next season - a goal they are currently eight points short of - could affect their ability to entice the very best to Old Trafford.
Defeat on Sunday would see United equal an unwanted club record of 10 Premier League losses in a calendar year, but there will be a lot more optimism around 2019 now than there was just a couple of weeks ago.
Recent form: DDWLWW
Recent form (all competitions): DWLLWW
It has been a difficult end to 2018 for Bournemouth, but when Eddie Howe takes stock of the year he will once again be pleased with another 12 months of progress.
The Cherries beat relegation by 11 points last season and are now 10 points better off than at the same stage of 2017-18, when they sat in the relegation zone at the halfway point of the campaign.
The fact that Howe's side now sit 14 points clear of the bottom three means that they will be able to keep their recent form in context and not be too disheartened by a run of eight defeats in their last 10 games across all competitions.
It is not a run Bournemouth can afford to let stretch too far into 2019, but during that time they have faced every member of the top six and after Sunday's match the fixture list does begin to get a little kinder once again.
Even so, it will be a concern for the Cherries that even the goals have begun to dry up; after scoring in 15 of their opening 18 games of the campaign, they have now failed to find the back of the net in four of their last five outings.
The most recent of those saw them ship five goals without reply against Tottenham Hotspur on Boxing Day, their heaviest ever Premier League defeat and one which leaves them with the worst defence outside the bottom five.
In the league alone Bournemouth have now lost seven of their last nine games - having only been beaten twice in their opening 10 - and they have particularly struggled on the road in recent weeks.
The Cherries have lost their last five away games across all competitions - failing to even score in their last three - and another defeat on Sunday would set a new club record of five Premier League away losses in a row.
It would take a major swing in fortunes for both clubs to avoid that fate, with Bournemouth having lost all of their last 10 matches against the established top six in all competitions.
Recent Premier League form: LWLLWL
Recent form (all competitions): WLLLWL
Lukaku has scored seven goals in six league games against Bournemouth - including six in his last three - but he is unlikely to risked unless he is fully fit, with Marcus Rashford having led the line in both games under Solskjaer so far.
Pogba is expected to start again following his brace against Huddersfield, but there could be changes elsewhere should Solskjaer look to rotate his squad, with the likes of Ander Herrera and Ashley Young among those pushing for a recall.
Bournemouth, meanwhile, will be without captain Simon Francis for the remainder of the season after he suffered a serious knee injury during the defeat to Tottenham.
Man Utd possible starting lineup:
De Gea; Young, Lindelof, Jones, Shaw; Herrera, Matic, Pogba; Lingard, Rashford, Martial
Bournemouth possible starting lineup:
Begovic; Rico, S Cook, Ake, Daniels; Brooks, Surman, Lerma, Fraser; Wilson, King
Head To Head
Bournemouth won their first ever Premier League meeting with United in December 2015, but they are since winless in their last six.
Indeed, that victory was one of only two Bournemouth have ever managed in 15 matches against United across all competitions. The most recent contest took place in November, when Rashford's injury-time strike rescued a 2-1 win for United at Dean Court.
The Cherries have never beaten United at Old Trafford before, losing six of their seven previous visits and scoring just two goals in that time.
We say: Man Utd 3-1 Bournemouth
It is difficult to go against the form book in this one. United look like a new team under Solskjaer whereas Bournemouth have a rotten record against the big clubs so far this season and may already be looking ahead to an easier run of fixtures in 2019 to return to winning ways.