Rashford broke the deadlock at Elland Road with a bullet header 10 minutes from time and has now scored 21 goals in all competitions this season.
"He's definitely one of them (best strikers in Europe)," Ten Hag told reporters. "From the first moment, I was really excited to work with him. I thought I could get more out of him and he has so many skills.
"He has such high potential and I think there can be even more. He can score more goals because he can score with his right, with his left and with his head."
Rashford's haul this season is only one fewer than his best goalscoring campaign in 2019-20, with 15 Premier League games remaining.
Ten Hag revelled in the atmosphere inside Leeds' Elland Road stadium but was not totally satisfied with his team's performance.
"I didn't feel the hostility. I think it was a great atmosphere. Great ambience," Ten Hag added. "It has to be in a rivalry. It has to be like this and we really enjoyed it.
"I am always critical. We have to play football early on in the game, be more calm. But if you're not that good in possession, you have to have good defensive organisation and win your battles," the Dutchman said.
"Until you have the first goal you have to keep doing that, and I think from that moment on there was more composure and the quality on the ball was better."
