Pogba shone for his country at Russian Federation 2018 where Les Bleus were crowned world champions, but the 25-year-old has been inconsistent since returning to Old Trafford.
"We have to start to win the games and I think we played well, like we played first half against Spurs, I think we did well".
He said: "I knew that they would change the majority of their players and the majority of the players that played will probably be on the bench on Sunday".
United manager Jose Mourinho is reportedly keen for Herrera to stay, having already utilised the player in a number of positions this season, including as an auxiliary central defender in the club's defeat at the hands of Tottenham.
Speaking about the game, Smalling said that he was happy with the number of chances they could make and now they should focus on converting them into more goals.
But since Alex Ferguson retired in 2013, United have failed to go close in either the Premier League or Champions League, while Barca have won three La Ligas in that time and the Champions League once. The World Cup-winning Frenchman, 22, can play in central defence or at left-back.
"I think he's dealing very well with the pressure".
Robson, who played for the Red Devils from 1981 until 1994, says that the World Cup victor, who was subject to interest from Barcelona this summer, is treated unjustly.
Fresh from a World Cup victory, much was expected from Pogba this season, but his performances have come in for criticism due in part to United's underwhelming start.
Spanish tax authorities allege the Manchester United manager owed 3.3 million euros ($3.8m).
Recent reports have claimed Pogba will remain at Old Trafford for the remainder of the season. The Hammers were booed off the pitch and Pellegrini, a former Premier League victor with Manchester City, faces a mammoth task to turn it around as the Londoners face Everton, Chelsea and Manchester United in their next three Premier League matches.