Watford’s run of 10 straight home wins came to an end at the hands of Wolves after a disastrous last 20 minutes at Vicarage Road.
An own goal was swiftly followed by a debut goal for Hwang Hee-chan as the visitors took all three points back to the Midlands.
Boss Bruno Lage, enjoying his first top-flight win, was delighted with the impact of his new South Korean marksman — especially given his limited preparation time due to the international break.
Lage said: "We didn't have too much time to train with him [Hwang Hee-chan] as he arrived after a 16-hour flight on Thursday — so we didn't have a lot of time.
"On Thursday he just trained for 30 minutes because of the flight and yesterday we prepared for the game.
"He saw videos of the good things we did in attack, the good things that we did in our defending, the way we press.
"It's good for him to start with a goal and he needs to continue giving what he did today."
The Hornets would have been feeling pleased with their work in the first-half, Jose Sa pulling off saves to deny both Moussa Sissoko and Emmanuel Dennis.
However, the momentum swung in Wolves' favour after the break.
Nelson Semedo wasted a golden opportunity in the 62nd minute, firing wide when he only had Daniel Bachmann to beat.
But Wolves did get their goal 12 minutes later —though they needed a massive slice of luck in the process.
Whilst attempting to clear the ball away low to the ground, Watford defender Francisco Sierralta, instead headed into his own net.
And with nine minutes left on the clock, the game was put to bed.
RB Leipzig loanee Hwang scored on his Premier League debut with a simple finish from close-range after Marcal’s initial effort had struck the upright.
Did you know?
Wolves earned their first away win in the Premier League since April (1-0 v Fulham), ending a run of four games without a win on the road.
The last two times Watford have lost three of their opening four Premier League matches, they would go on to be relegated in both campaigns (2007-07 and 2019-20).
Wolves’ first Premier League goal of the season, which was an own goal, came after 69 shots of their own.
Since scoring three goals on the opening day, Watford have failed to score in their last three Premier League games — their longest goalless run in the competition since December 2019.
Hwang Hee-chan became the eighth Wolves player to score on his Premier League debut.