The Red Devils were on the verge of their third Premier League defeat of the season, before Daley Blind scored a late equaliser.
"We also have to look for physical balance and maybe that is our problem," BBC Sport quotes him as saying. "I am always looking for creative players and in England you need physical players as well, maybe [Marouane] Fellaini brings that.
"We could do better with our philosophy and we are improving now the players are beginning to understand our formation and philosophy more, which is why it's such a shame that they didn't get a result tonight.
"It's not too good after eight games but when you see the games we are normally the better team but we have eight points too few."
United are currently sixth in the Premier League table.