The Bees snatched a draw when Joe Devera grabbed a last-minute equaliser to cancel out Wes Thomas's 61st-minute opener for the Robins.
Yates said: "It's the way it goes, we've got to work even harder on Tuesday and scrap again.
"The performance deserved more. It was never going to be a pretty game in terms of the pitch, in terms of coming back from a 3-0 home defeat. It was never going to be one where we turned someone over with ease.
"We had to earn the right to play, and we did it, and more than enough. Brown's had one or two shots from distance to save and then we've conceded a stupid goal at the end.
"It's a poor goal to give away, especially considering the timing but you can't legislate for that."
Source: PA
Source: PA