Ten Hag takes the blame for Manchester United squandering another lead
The three-time European champions blew a two-goal lead twice in Istanbul, with goalkeeper Andre Onana making two costly errors, to leave their hopes of reaching the last 16 hanging by a thread.
United are bottom of Group A with four points from five matches but still just one point adrift of Copenhagen and Galatasaray. They must beat group winners Bayern Munich on December 12 to progress.
United let a two-goal lead slip in an earlier group game in Copenhagen before losing 4-3 and Ten Hag said their inability to see games out was down to him.
"It's always me (who is to blame for throwing away leads). I am responsible for this, but also know we are in a project," the Dutchman told TNT Sports.
"We are in the right direction, so I know where we have to go and which steps we have to take and I'm sure we will be successful in the long term.
"If we want to stay in the Champions League, we have to win the next game."
Ten Hag was confident they would find a way to stop conceding so many goals.
United have scored the most goals in their group with 12 but are tied with Celtic for the second-worst defensive record in this year's Champions League, with 14 scored against them.
Only Antwerp in Group H have conceded more (15).
"We will fix that but I'm very pleased, you see the style of the team," he said. "Proactive, dynamic, brave, so it's what I said, I'm really pleased with the performance."
Ten Hag's side next travel to Newcastle United in the Premier League on Saturday.
