That loss to West Brom handed United's bitter rival City the Premier League title and Mourinho's side looked eager to put things right at the Vitality Stadium, ultimately cruising to a victory which sees them head into Sunday's (AEST) FA Cup semi-final clash with Tottenham in confident fashion.

For all of Mourinho's changes, the breakthrough came through Chris Smalling, one of the four players to keep their place in the team, as he was left with an easy finish following good work from Ander Herrera and Jesse Lingard.

Bournemouth was by no means outclassed by their visitors in the first half, though United's improvement from Monday's West Brom horror show was significant.

Nevertheless, it was fortunate to avoid conceding a penalty early in the second half when Luke Shaw barged Callum Wilson to the ground.

And United went on to capitalise on that let-off, as Romelu Lukaku – a second-half substitute – produced a fine finish to end Bournemouth's hopes rescuing a late point.

Anthony Martial was one of those to benefit from Mourinho's tinkering and the Frenchman quickly looked to take the initiative, threatening in the third minute as he linked with Paul Pogba and beat Steve Cook, before seeing his cut-back blocked behind by the Bournemouth defender.

United had little difficulty dictating the tempo, though they looked defensively susceptible at times and got lucky in the 11th minute, as Jordon Ibe shot just wide of the bottom-left corner after Wilson had exploited space in the visitors' backline.

At the other end, Asmir Begovic was eventually forced into a first save 28 minutes in – Marcus Rashford drilling at him from a tight angle, winning a corner.

And as a result of pressure from that corner, United broke the deadlock.

Herrera sliced open the Bournemouth defence to find Lingard and he squared across the face of goal for Smalling to tap in.

United exerted pressure further up the pitch upon the restart and kept Bournemouth penned into their own area for periods, but it was lucky to not concede a penalty in the 56th minute.

Josh King played the ball across the face of goal and Wilson looked destined to tap in, only for Shaw – making his first Premier League start since February 3 – to nudge him over and escape punishment.

Mourinho stepped things up soon after by introducing Lukaku for Lingard and the Belgian quickly made an impact, racing on to Pogba's throughball and lifting a fine first-time finish over the approaching Begovic with 20 minutes to go.

Bournemouth enjoyed some late pressure, but De Gea's goal and United's lead was never threatened.