Chris Smalling has admitted he has had to develop a thick skin as Manchester United's defensive problems continue.

Callum Wilson's goal for Bournemouth on Saturday was the 18th United have conceded in 11 Premier League games this season -- more than West Ham, Brighton and Crystal Palace.

Manager Jose Mourinho branded the defending in the first half at the Vitality Stadium "awful" while regular centre-backs Smalling and Victor Lindelof have had to deal with their share of criticism from some supporters.

"You can't get away from it [the criticism] but I'm not going to sit there and read all my comments [on social media]," Smalling said.

"I think as players you need to have thick skin. It's about making sure you have more good days than bad."

Smalling is into his ninth season at Old Trafford after joining the club from Fulham in 2010.

Mourinho has spent more than £60 million on centre-backs since taking over in 2016 but Smalling was still trusted to play nearly 50 games last season and the 28-year-old has been a regular in the team again this term.

"To be able to be a club like this and last as long as I have you need to have that courage and belief in your ability," Smalling said.

"You won't have good days every week and the bad days are often highlighted when you're at a big club. I believe in myself and I keep working."