Shaw and fellow United and England defender Chris Smalling were the subject of Mourinho’s post-match rant following the 3-1 win over Swansea in the Premier League.
The two missed the victory at the Liberty Stadium through injury, leaving Mourinho forced to play a makeshift defence of Matteo Darmian, Daley Blind, Marcos Rojo and Ashley Young.
That caused Mourinho to question their resolve, saying: “In every sport, many times you play and you are not 100 per cent.
“To compete, you have to go to the limits. It’s a cultural thing for some, and that’s not my culture.
“There is a difference between the brave, who want to be there at any cost, and the ones for who a little pain can make a difference. For the team you have to do anything.”
But Lallana, who played with the 21-year-old at Southampton, rejected that claim and insisted Shaw is both physically and mentally tough after recovering from a broken leg that caused him to miss 10 months of football.
"I was with Luke Shaw at Southampton," he told the Daily Star.
"He's a very strong boy. He's had a horrific leg injury. You don't come back from that without being mentally and physically strong.
"You don't come back from a leg break like he had without having difficult times mentally on your own."Reuse content