United romped to a 4-0 success at Old Trafford to ensure they finish the first round of Premier League games top of the table.
And Shearer reckons the rout was the best the Manchester giants have played during Mourinho’s spell in the hotseat.
“I’d say it was the best performance under Mourinho,” he said on Match of the Day 2.
“It had edge, pace, energy to it in every position.
“It was enjoyable to watch.”
Shearer was also full of praise for striker Romelu Lukaku, who netted twice for United.
“It was a complete centre-forward performance,” the ex-Newcastle man added.
“He was aggressive, he had pace, he gave his team-mates options, his touch was good.
“When you look at a centre-forward he has to give you goals and he did that today.
“He was just superb, and horrible to play against.”
