Root won the toss under grey skies at the Adelaide Oval but the tourists were not able to make the best of the conditions as Australia closed play on 209-4.
England bowled better as the day went on and Overton, who dismissed Australia captain Steve Smith for his first Test wicket, believes it was the right decision.
He said: “We were happy to bowl first, there were overhead skies and we felt we could get a few early ones.
“We bowled pretty well all day but we didn’t get the nicks we deserved really. We will come back in the morning and hope to get some early ones.
“We feel pretty happy, obviously we would like a few more wickets but over the day we felt we bowled pretty well.
“They played and missed a few times and if we come back in the morning and get a few early ones we’ll feel we’re on top.”
Overton could not have asked for a bigger scalp as his first in Test cricket as he bowled Smith, who was looking ominous, for 40.
“It was a little bit of a cross-seam ball and it skidded on a little bit, which was nice and almost beat him for a little bit of pace,” he added. “We had a little bit of banter where he was saying I was so slow. That’s a part and parcel of it.
“I found out about an hour before the warm-up that I was playing so it was a nice chat with Rooty there but I had to make sure I got my head down and was ready for play.
“It was nice to get out there, it was frustrating with the rain early on and once I got the ball in hand I was OK.”