The Red Devils are in third place in the Premier League table after a 3-0 victory over Everton at Goodison Park on Saturday afternoon.
With the money they’ve spent and the players they have, United are more than capable of winning the league
However, Van Gaal has been starting Blind in an unorthodox centre-half position this season, whilst Ashley Young has been filling in at left-back.
But the United manager altered his tactics for the trip to Everton after a 3-0 rout at Arsenal, with Marcos Rojo at left-back, while Phil Jones partnered Chris Smalling at centre-half.
And former Liverpool midfielder Redknapp believes the result highlighted why Van Gaal must start players in their orthodox positions if United harbour ambitions of winning their first title since 2013.
“Against Arsenal Louis van Gaal got it badly wrong,” Redknapp said in Daily Mail.
“Ashley Young and Daley Blind are not natural defenders. If they had played on Saturday, Romelu Lukaku would have eaten them up.
“But Van Gaal realised his mistake and went back to Chris Smalling and Phil Jones. They relished the battle. And with Marcus Rojo and Matteo Darmian, Van Gaal had a proper defensive unit.
“With the money they’ve spent and the players they have, United are more than capable of winning the league. And with the Manchester derby up next week, they have to build that challenge around a solid defence.”
The Red Devils are in third place and two points behind leaders Manchester City.
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