The January signing scored the only goal of the game within eight minutes of coming off the bench, sending the travelling Saints fans wild.
The goal ensured Saints made it back-to-back victories at Old Trafford, and Austin was thrilled to have the opportunity to make his mark.
“It was nice to make my debut and even better as a striker to score, but more importantly we got the three points to continue our run,” Austin told youtube.com/southamptonfc
“When I come on the pitch if a chance comes I want to make sure I put it away. The chance came and I scored, but the most important thing is the win.
“It was a scrappy game and it was always going to be about that one moment. Luckily enough it came for Southampton and we’ve come away with the three points.
“Obviously last year winning 1-0 meant confidence was high, plus we came off the back of two home wins and thankfully we’ve been able to continue that run.”
The goal was a big moment for Austin as he looks to make his mark at Saints following his January move from Queens Park Rangers, and the striker was pleased to have got up and running straight away.
“I’ve got the first goal, which I’m delighted with. Hopefully now I can push on and score some more, but more importantly put in performances,” Austin added.
“Ronald said to get on and put a shift in, and if I got the chance, make sure I put it away. Luckily enough that’s what I did.
“A January move can be tough for anybody and you need to try and hit the ground running.”