The Australian international, who officially joined Villa earlier this month, played a neat through ball to Delfouneso who turned and hammered home a low ball two minutes before half-time to give Villa victory at PPL Park in the pre-season friendly.
Villa boss Paul Lambert, who played a fairly experienced line-up, was delighted with the way his side played in very trying conditions.
"It was a very good workout. I thought we were excellent, certainly for good spells of the game," he told AVTV.
"I thought it was tough for us with the heat but I was delighted with the way we played.
"I thought we should have been two or three up before we did score but the football we played was excellent. I was really, really pleased.
"It's not an easy place to play with their crowd but I was really pleased with my team.
"The passing pleased me but also the commitment. I think that's always important as well.
"You can't play without commitment. This last fortnight we've been at it. The lads have been great." Villa's summer tour of the US continues in Chicago with a meeting with the Fire at Toyota Park on July 21 prior to the July 24 clash with Portland Timbers at JELD-WEN Field.