The proud Texan struck his first Spurs goal in the middle of an incredible scoring spell at the start of the second half, as Andre Villas-Boas's team won 3-2.
He said: "It was a rollercoaster to go 2-0 up and then they scored and we responded again.
"In the second half it felt like we were chasing shadows.
"I've been in England for five years now and that's the first time I've won at Old Trafford. I was feeling the pressure so it was good to open my scoring account.
"It's always difficult here. The second half was so tough because if you press them then Paul Scholes just passes it around you."