Onana was culpable for all three of Galatasaray&aposs goals as United squandered a two-goal lead to draw 3-3, leaving them still at the foot of Group A in the Champions League with one game to play.
United bought Onana from Inter Milan for 47.2million in July and although he has enjoyed a steady and impressive period domestically of late, his Champions League performances have been littered with errors.
Back-up goalkeeper Altay Bayindir, a 4.3m arrival from Fenerbahce on transfer deadline day in September, is yet to make his United debut but could play in six successive games in January and February if Onana participates for Cameroon at the Africa Cup of Nations.
Onana is understood to be concerned he could lose his place if he is called up by Cameroon but Ten Hag suggested he would not be demoted in any of United&aposs upcoming matches.
Players always need trust,” Ten Hag stressed. “I just explained he is after Alisson the best stopper in the league from preventing expected goals. You deserve to play.
No, that (players losing confidence in Onana) will not happen. This dressing room is together. Football is a game of mistakes and everyone can make mistakes. But this team has to cover that so we will operate.
No (he will not be dropped). It is obvious. He has the potential. It wont help [to drop him]. I have trust in Tom (Heaton) and Altay, clear. But Andre, you see after Alisson, he prevented the most expected goals in the whole league.
“In the Champions League, he has so much experience with Ajax and last year with Inter Milan. Last year, he was with (Manuel) Neuer and (Thibaut) Courtois the best goalkeeper, so he is a great keeper.
“He has the potential, so we have to work on him so that he does it consistently and we will work with him and we will support him. The manager, coaches and players all support him.
Ten Hag stressed Onana is not undroppable and that discussions over his possible participation in the AFCON are ongoing. Onana left the Cameroon World Cup squad in Qatar last year after a fall-out with coach Rigobert Song and was not called up again until September.
United sources suggested at the time of Onana&aposs signing he would not return to the Cameroon squad. Onana could miss up to six United games as the AFCON starts on January 13 and runs until February 11.
Of course not. Nobody is undroppable, that is also clear,” Ten Hag said. “We have a strong belief that he will help us win trophies.