Published: 2021-10-25 14:03:38 BdST
Egypt forward Mohamed Salah scored a hat-trick as Liverpool humiliated United, who are now without a win in their last four games and have slipped to seventh on the Premier League table, eight points behind leaders Chelsea.
"Sometimes the result is not the one we fight for. Sometimes the score is not the one we want. And this is on us, only on us, because there's no one else to blame," Ronaldo, who returned to the club in the summer for his second spell, said on Instagram
"Our fans were, once again, amazing in their constant support. They deserve better than this, much better, and it’s up to us to deliver. The time is now!"
Defender Luke Shaw, who made a series of defensive errors alongside captain Harry Maguire on Sunday, echoed Ronaldo's comments.
"We are extremely disappointed, it is not good enough and it hurts a lot," Shaw told the club. "I think football is obviously a team sport, we are in it together and we are all together.
"But I think, as individuals, we need to take responsibility for some of the actions tonight (Sunday)... I have not been at my best and I know that, for maybe the last few weeks, so I need to reflect on that."
United travel to Tottenham Hotspur in Saturday's league game.