The Championship sides’ quality showed in the opening 45 minutes as they crashed in three goals in the space of 15 first-half minutes.
Dale Stephens, Tomer Hemed and Beram Kayal were all on target before Reds improved in the second half and more than matched their visitors.
Yates admitted his side was given the run around before the break but once they took on board their jobs at half-time, he was pleased with the performance after the interval.
He said: “Our pre-season is tough, from Burgess Hill to Fulham to Brighton, it’s a tough ask in only our third game, but it is what you want.
“You want to play decent sides, you want to learn from them and you want to see decent things.
“That’s what tonight was about, we saw things that we didn’t like, we saw things that we know we can improve on, but we also saw one or two decent things as well.
“Although the scoreline isn’t too clever we take something from every game, whether it’s a negative or a positive and get on with tomorrow to make sure we are ready.
“Always the object is Oxford - first game of the season - and then beyond that. It’s not about winning and losing in pre-season games, it’s about getting something put of every single game.
“It’s about players getting game time - we have had 90 minutes for Simon Walton, Joe McNerny, Luke Rooney - who I thought was excellent - and Gwion Edwards has played 87 minutes something like that, so it’s things ticked off.
“We know we have got to improve but we will.”