However, all that hard work was undone when the Dutch midfielder - with the deadlock yet to be broken - was sent off for a second bookable offence after 62 minutes, after which the hosts simply unravelled with 10 men against the unbeaten league leaders.
Within six minutes of the dismissal City were 2-0 up, with Erling Haaland striking first before a wonderful curling effort from substitute Jeremy Doku.
Gravenberch - though available for Wednesday’s trip to LASK Linz of Austria in the Champions League - will now serve a one-match suspension during Saturday’s clash with Brentford in the Premier League, leaving Iraola with a potential shortage of midfield options if Szoboszlai is still sidelined.
Game-turning moment: Ryan Gravenberch’s dismissal sparked a collapse from Liverpool against Manchester City
Getty
However, there has been much debate regarding his sending off, with Gravenberch first booked for a foul on Elliot Anderson before receiving his second yellow for bringing down Doku on the counter-attack.
And while Rooney agrees that the initial caution was unfair, he blamed Gravenberch for not being more careful when already on a booking.
“I think the first yellow card is harsh,” the Manchester United and England legend said in his role as a pundit for BBC’s Match of the Day.
“He’s obviously gone for the ball, it’s a poor touch by Elliot Anderson and he just nicks him and catches him on the top of his foot and he goes down. So it’s probably not a yellow card.
“But for me, the second one is. When you’ve been booked and you’re on a yellow card, then you leave yourself in a position where you can get a second yellow card and sent off.
“So it’s a bit naive and stupid for that second yellow card.”
On his analysis of City’s first game since their guilty verdict, Rooney also doubled down on previous claims that he would not want to be retrospectively awarded another Premier League title in the event that City were stripped of the trophies won during the period in question.
United finished as runners-up to rivals City both in 2011/12 - when Rooney and Sir Alex Ferguson were still at the club - and again in 2017/18 under Jose Mourinho.
“It’s difficult,” he said. “I look at it from a player’s point of view. For those players, they went onto the football pitch and they won the league. We finished second, we didn’t finish first. I wouldn’t want a medal for finishing second.”