Nemanja Matic enjoyed a winning debut as Manchester United wrapped up pre-season preparations with a 2-1 victory over Sampdoria in Dublin on Wednesday.
Juan Mata scored a later winner to ensure United will enter next Tuesday's UEFA Super Cup clash against Real Madrid on a winning note, after Henrikh Mkhitaryan's header had been cancelled out by Dennis Praet.
Matic, who completed a £40million move from Chelsea on Monday, started at the base of midfield and looked comfortable throughout his 45 minutes.
The Serbian's composure helped the Europa League winners maintain control throughout the opening period, but a series of half-time changes stifled their momentum.
Belgian midfielder Praet equalised for the Serie A side just after the hour, leaving Mata to assume the role of match-winner for Jose Mourinho's side inside the final 10 minutes.
United began with a back three of Victor Lindelof, Chris Smalling and Daley Blind, while Mourinho also handed a start to young midfielder Andreas Pereira, who is tipped to figure in the manager's first-team plans this season.
Calamity almost struck the new-look defence as early as the seventh minute when David de Gea was forced to claw a wayward Blind backpass off the line, gifting Sampdoria an indirect free-kick on the edge of the six-yard box.
Thanks to a wall of bodies they survived and, incredibly, raced straight up the other end to open the scoring through Mkhitaryan, who nodded into an empty following a superb dipping cross from Matteo Darmian.
Sampdoria might have equalised from a ball over the top moments later only for Fabio Quagliarella's stretching first-time finish to drift wide of an empty net.
Mkhitaryan should have doubled his tally in the 22nd minute, but the Armenia international this time headed Antonio Valencia's whipped delivery straight at Christian Puggioni.
Romelu Lukaku next flashed a curling shot around the post as United began to control proceedings at the Aviva Stadium, but Sampdoria steadied and saw out the remainder of the first half.
Mourinho replaced his entire midfield at the break and switched to a back four on the hour, pairing Lindelof and Smalling in the heart of the defence.
The reshuffle proved costly in the 63rd minute when Smalling failed to clear Karol Linetty's cut-back, the loose ball falling kindly for Praet to drive home.
Chances began to dry up until the final 15 minutes when the Red Devils pressed forward more regularly and almost recaptured the lead through Ander Herrera.
Mourinho's men did get the winner in the 81st minute courtesy of Mata, who coolly stroked Anthony Martial's squared pass into the bottom corner and sent United to Skopje in winning form.
