Ten Hag admits they're counting on Ugarte to make the No6 role his own.
Ahead of facing West Ham on Sunday, the United manager said: "For sure, the six position is a key position in your team, and (Ugarte) has to learn this position in our game model. I think today is a step forward, so I'm really pleased with his performance, and from here on he has to build on it.
"We have to stay patient but, as you see, if the quality in that position is not right, it's very difficult for a team to control games, and then I don't even speak about dominating games. So, that position needs one who brings the quality all the time, and we have to integrate him now in this team. As I said, I was pleased with his performance (against Fenerbahce) and from here on he can build up."
On whether No6 is a position they've been lacking in, he added: "No, we have Casemiro. Lately he's been doing very good again. We have people there who can fill in that role. We have Kobbie (Mainoo) and I think Christian Eriksen is doing brilliant in this moment."