Eyebrows were raised before a ball had been kicked as midfield star Ella Toone was left out of the starting XI, alongside striker Elisabeth Terland.
With goalkeeper Tullis-Joyce absent and Middleton-Patel making just her second senior appearance for United – her first at Old Trafford and in the Champions League – there were anxious fans.
And Wales international Middleton-Patel was immediately given a taste of the elite level when Jennifer Echegini’s powerful effort bounced back off the inside of the right post within two minutes.
United left-back Sandberg had her hands full, with Nigerian international Rasheedat Ajibade sprinting relentlessly down the wing, and PSG dominated possession.
But in Malard, United always had an outlet.
She was quiet until the opportunity arose for her to go one-on-one with French compatriot Mbock Bathy and she did not disappoint, reading the flight of the ball from Jayde Riviere effectively, using her body to hold off the PSG centre-back and firing perfectly past Earps into the far corner.
Earps slid to her knees in disappointment, though she could do very little to stop Malard’s precise finish, and United were up and running.
PSG later showed their individual quality when Carmona took advantage of the space afforded to her to shoot from distance, looping the ball expertly over Middleton-Patel, who, like Earps, was helpless.
But the near-15,000 in Old Trafford found their voice in the second half as Park’s dazzling feet helped create Rolfo’s goal to make it 2-1, before Earps dived well to her left to block Malard’s dangerous effort at the near post shortly after.
Despite PSG’s attempts to find an equaliser, it was United who looked more assured, proving they belong among Europe’s elite and going toe-to-toe with the French giants – who have reached the semi-finals in four of the past five seasons.
England international Park was at her sparkling best, Gabby George filled in at centre-back superbly and Malard brought the necessary magic as United ensured Earps’ return was not a celebratory one.
But for all the controversy surrounding Earps, there was a warm farewell from United fans at full-time as she walked along the stands applauding them – despite receiving a few pantomime boos throughout the game.
It will sound alarm bells for PSG, who have lost all three league phase matches this season, increasing pressure on head coach Paulo Cesar.
