Ryan Giggs joked with Daniel James that he would not select him in Wales' next squad if Manchester United lost Saturday's derby.
James played the entirety of the Reds' 2-1 victory and assisted Anthony Martial's 29th-minute strike.
It was another impressive individual performance by the summer signing from Swansea, who is also making waves at international level with Wales.
He has started each of his country's last nine matches under Giggs, playing a key role in their qualification for Euro 2020.
However, James might have been left sweating over his spot in Wales' squad for next summer's tournament had United failed to get a result against their local rivals.
"I told him if he doesn't win today I'm not picking him!" Giggs joshed.
Former United goalkeeper Peter Schmeichel hailed United's performance at the Etihad and singled James out for special praise for his showing on the right flank.
"Today was a big day for them (United), they now have an incredible belief," Schmeichel said. "In the same week that they beat Tottenham, they've beaten Manchester City. That's got to mean something for them.
"I think tactically today they got it absolutely perfect in terms of how they were exploiting Man City's weaknesses. Man City are 14 points behind [Liverpool] because they can't defend, it's as simple as that.
"Laporte is out, they haven't replaced Kompany, and you think you're watching the champions. Owen [Hargreaves] said before that they can concentrate about winning the Champions League - but they have to defend much better than that. That was exploited by Manchester United today.
"Someone who is not going to grab the headlines... I want to just say Daniel James was unbelievable, he was chasing every ball, he was in every counter-attack and at the same time he was doubling up with Wan-Bissaka on the right-hand side and, Ryan, you must be so happy to see one of your players from Wales performing so well.
"He's played every single game this season and he's still playing well. That is a fantastic signing and he played fantastic today."
