Debutant Dom Dwyer and Kellyn Acosta were on target to give the Stars and Stripes a 2-1 victory over the Black Stars at East Hartford in Connecticut.
Veteran Asamoah Gyan fetched Ghana's consolation from a free-kick, having earlier missed a first half penalty.
"It was a good test for our team," Arena said.
"All 90 minutes, we had to be in it mentally, had to be smart tactically, and we were able to do that.
"When we play Ghana, they have excellent pace all over the field and they get at you a couple of times, and they certainly did that today."
The meeting was the fourth encounter between both teams, and the US' win now makes it two victories apiece.
Interestingly, all four clashes have ended in 2-1 scorelines.
"I think we fouled in some areas of the field where Ghana was very dangerous on set pieces and scored a terrific goal," Arena continued.
"We conceded too many free kicks in dangerous spots. We got caught a couple of times on the counter, which is to be expected."
The US now move their attention to the upcoming Concacaf Gold Cup, which starts on July 7, where the Stars and Stripes will play against Panama, Nicaragua and Martinique in Group B.