A diligent Australian defence prevented England from creating clear-cut chances in the first half, and Watkins came the closest in the opening 45 minutes as he rounded Matt Turner but his effort from a tight angle hit the post.
Australia were limited to counter-attacking opportunities and their best chance came shortly before half time as Ryan Strain’s low strike inside the area beat Johnstone but Lewis Dunk was on hand to clear the ball off the line.
England stepped up their efforts after the break and were rewarded in the 57th minute when Trent Alexander-Arnold picked out Jack Grealish with a fine cross. The Manchester City midfielder was able to get the ball down and fire an effort towards goal and Watkins was on hand to poke home from two yards out.
When asked about his goal after England’s win, Watkins said: ‘I think Jack [Grealish] has gone to shoot and he’s dragged it, I don’t know if it’s going in.
‘My first thought is that it was, but I took it off him, look, when you get the opportunity you have to grab it with both hands, I had to take it off him even if it was going in.
‘I said [to Grealish] I didn’t know if it was going in, not sorry, but I was kind of looking at him saying I’m not sure. I knew I wasn’t going to come off this pitch without a goal, I just had to keep arriving and knew I’d get a chance.’
Marcus Rashford was brought on in the 61st minute and looked dangerous on England’s left flank.
However, Southgate’s side were unable to find a second, while several substitutions also disrupted Australia’s flow towards the end of the game.
England now face Italy in their Euro 2024 qualifier at Wembley on Tuesday evening.
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