The Red Devils began their preparations for the 2023-24 campaign with a 2-0 victory over Leeds United in Oslo, with Noam Emeran and Joe Hugill on the scoresheet in the second half of the contest.
Man United were missing a number of first-team players, with many not making the trip to Oslo, but the likes of Aaron Wan-Bissaka, Raphael Varane, Lisandro Martinez and Jadon Sancho were involved, while Mason Mount made his debut for the 20-time English champions.
"It's the first game and I think we have seen some good things. We've already trained over the last year, so we have a good foundation. You can see that in the game," Ten Hag told MUTV.
"But yeah, also some young lads came in and they fit in. We are now one week [into] training. We presented the rules and the principles. And what I see, what can I say: we have seen some good stuff.
"They're coming in and it's a big moment when you are coming up in the squad, in the first team. You deserve game time because over long years you work for it.
"And then that moment in a very good and nice stadium, with a good crowd, and in such ambience they're coming in and then score and win the game. That's very good and nice."
Ten Hag also praised central defenders Martinez and Varane, with the former back after a foot injury, and the latter wearing the captain's armband for the Red Devils.
"Licha was, in the last part of the season, injured, and you still can see he's now on his way back. So he worked very hard during the summer and now he's returned for the first time back in the game. But you see he's a little bit lacking in rhythm but you also see Rapha and Licha fitting very well together, they're very solid.
"He's (Varane) fantastic. He's had a fantastic personality from the first moment I met him and, of course, I know him over the years and what he already achieved at Real Madrid and at France.
"That's unbelievable. You think when you are young, you can hardly believe you can achieve such things. But Rapha did. So that is so huge. And so we are full of respect from everyone around United internally and also you see the fans they admire him."
Ten Hag also paid tribute to Mount's performance, with the club's new number seven making a positive impression in his first 45 minutes on the field.
"Oh [he was] great, but we could expect this. He has so many skills and I'm sure we will take so much joy from him. He will contribute to our performance, absolutely," he said.
Man United will also take on Lyon, Arsenal, Wrexham, Real Madrid, Borussia Dortmund, Lens and Athletic Bilbao as part of their preparations for the 2023-24 campaign.