United, seventh in the standings and six points off the top four, have failed to score in their last three games, losing to Bournemouth and Bayern Munich before a goalless draw at Liverpool.
Ten Hag has had to contend with a string of injuries and is without the services of Casemiro, Lisandro Martinez, Mason Mount, Tyrell Malacia, Victor Lindelof and Amad Diallo.
"I think what has definitely hurt (us) was we had, in crucial positions, we had the problems," Ten Hag told reporters on Friday. "You have to deal with that.
"But everyone understands when you have such key players who are not available, it will have a negative effect on results. Still, we are in a place where we can change this story, change this season.
"I am confident, when the players are back, we will have a good and strong squad. Liverpool were top of the league (last weekend), so we were competitive with them... This team, this squad, is strong when everyone is on board and we can beat anyone."
United travel to West Ham United on Saturday, before hosting second-placed Aston Villa on Tuesday.
