Jose Mourinho praised Henrikh Mkhitaryan's determination to prove himself at Manchester United after the Armenian midfielder scored a stunning solo goal in the Europa League win over Zorya Luhansk.
Mkhitaryan, a former Shakhtar Donetsk player, marked his return to Ukraine with his first goal for United after weaving through the Zorya defence early in the second half.
Zlatan Ibrahimovic's late goal secured a 2-0 win to confirm United's progression into Monday's draw for the round of 32.
And with Mkhitaryan showing his quality after initially struggling to impress following his summer arrival from Borussia Dortmund, Mourinho said the player's resilience has helped him to win his place.
"He was strong mentally and very determined to fight against his difficult adaptation," Mourinho told reporters after United's victory.
"He is doing that in the best way -- he worked really hard physically and tactically.
"We knew the talent was there and what we were buying, but we had to improve him tactically and physically.
"Now he is playing well in the Premier League and Europa League, and the goal means more happiness for him."
United's win was their first away from home in Europe since August 2015 and extended their unbeaten run in all competitions to seven games.
And despite having seen his team throw points away by conceding late equalisers against Arsenal and Everton in the Premier League recently, Mourinho said United were now showing signs of progress.
"One thing is to play bad and get bad results," Mourinho said. "That kills confidence.
"But when you play well and don't win, you always have the hope to win, and we are playing well.
"The reality is that nobody has been better than us. Nobody was better than us. In the players' brains it works and we were always better than our opponents."
Mourinho, meanwhile, urged UEFA to be lenient with Zorya after a firecracker thrown from the stands in the first half narrowly missed United goalkeeper Sergio Romero.
A second flare was lit and a firework thrown, with laser pens also shone in the eyes of United defender Daley Blind, and Mourinho said the incidents spoiled the atmosphere.
"The support was beautiful and they don't need that because they just make it more dangerous for the goalkeeper," he said.
"The stadium was beautiful, fans good, you just don't need these things.
"Maybe UEFA will not be happy and now take some money from Zorya, but I don't think Zorya deserve that."