In what was their penultimate friendly of the summer, a brace from Karlan Grant and an own-goal from Yoav Sade saw the Baggies run out comfortable winners at the Kassam Stadium.
But on a day that saw a heatwave engulf the UK, temperatures in the region of 40 degrees led to an incredibly flat game of football.
Neither side truly created a chance of note before the 70th minute with very little quality on show.
But a late flurry from Albion saw them claim the win in what was their fifth pre-season outing in 15 days.
"Let's talk about the second-half," Bruce said when asked about his team's display.
The first-half was typical 38 degrees. There was a bit of rain that helped a little bit.
"And as soon as it cooled down slightly, then we were able to go to the level we needed to get to.
"Second-half was far, far, better. The most important thing is that everyone came through unscathed.
"We've got one or two little knocks. Big Dara (O'Shea) was missing because he had a baby. Robbo (Callum Robinson) has a knock but should be available for the weekend. In that respect it was good.
"But the second-half was much better than the first."
Grady Diangana also missed the trip to Oxford with an ankle problem.
"He is okay I think," Bruce added.
"We'll have to see how he goes for Saturday. He had scans yesterday but we don't think it's that bad.
"You can see he's turned his ankle but we think he should be okay."