WATCH a FULL MATCH REPLAY of Manchester United v Leeds at 10pm on beIN 3, via MUTV | Foxtel, Kayo, Fetch & CONNECT
Sancho played his first game since 22 October when he came on from the bench against Nottingham Forest earlier this month, having missed an extended period due to what Ten Hag described as "circumstances with fitness and mood".
The England international was introduced as a second-half substitute with United 2-0 down, as Wilfried Gnonto's early strike was followed up by an own goal from Raphael Varane.
However, Marcus Rashford halved the arrears with his 20th goal of the season before Sancho's effort squirmed through the clutches of Illan Meslier, denying manager-less Leeds a first league win at Old Trafford since 1981.
Ten Hag hopes Sancho's display is a sign of things to come, saying of his introduction: "I wanted a different dynamic. In that moment we weren't in the game.
"Luckily it succeeded because we scored two goals. We're very happy.
"He's all the way back. We know he's a magnificent player. I think he can consistently have a big impact, but he has to work hard.
"It will motivate him to get more. I really enjoyed it, especially for him. It will strengthen him."
While Ten Hag was pleased with United's improvement over the course of the match, its slow start left him with a sour taste, given Gnonto found the net just 55 seconds after kick-off.
"It's mixed feelings. Of course in the end we were happy to win a point – but we dropped two points," he said. "It's a very bad start, unacceptable, especially in a derby you have to be ready to battle and take responsibility. We didn't do that.
"I have to complement the team and their resilience to fight back. We made two great team goals."
United will soon have the chance to go one better against its old rival, as it heads to Elland Road on Monday (AEDT) for the second instalment in a rare Premier League double-header.
After witnessing Leeds produce an energetic display, Ten Hag called on his team to win more duels next time out.
"We knew before how they would play with attitude and style. We didn't know what system they would play but you have to be ready and read the game," he said. "Definitely you have to win your battles. That is for everyone to take the responsibility. If you win those individual battles, you will win this game."