Hughes up for the challenge
Both sides were winless heading into the clash at Loftus Road, and Rangers were 2-0 down at half-time thanks to goals from Rickie Lambert and Jason Puncheon.
Junior Hoilett gave the Loftus Road faithful some hope soon after the break, but a late own goal from Anton Ferdinand sealed the result.
With speculation regarding Hughes' future in the QPR hot seat intensifying in recent weeks, the Welshman said he would not shy away from the mammoth task ahead of him.
"I don't run away from challenges," Hughes stressed to reporters after the match.
"This is a challenge, it's a huge challenge, it was a huge challenge when I undertook it in January.
"There weren't too many people queuing up for the role when I decided this was the right role for me and the job I wanted to take on.
"I knew it was going to be problematic, we all understood that, but this year obviously we had real expectation and I was quite prepared to raise expectation as I thought we'd have a good season and it hasn't happened for us unfortunately.
"And because of raising expectations, more people are going to be disappointed, and that's the case as we find it now."
QPR were booed off the pitch at the final whistle, and Hughes said he shares the fans' concerns and slammed a lethargic performance.
“(It was the worst performance of the season) without a shadow of a doubt," he said.
"I can well understand the reaction (of the fans), in fairness it's exactly my reaction to that performance.
"We're not going to hide behind trying to make a positive out of a very big negative today.
"It was a huge game for everyone connecting with Queens Park Rangers, including myself, players, staff and fans, and we haven’t performed unfortunately."
Southampton boss Nigel Adkins, meanwhile, credited his side's maturity and resolve for being able to secure their first league win of the season.
"We got on the front foot, which was important. We believe we can pass the ball - we've demonstrated that on numerous occasions this season," he said.
"There was a good resolve - we're growing in maturity all the time. We've a young group of players who are learning lessons very, very quickly and there's been several good performances of late.
"We knew QPR would come at us in the second half, but the players dealt with the situation very well. We had good game management, and all credit to the players. It was an excellent three points away from home."