Tom Cleverley’s injury-time winner sent Watford fourth in the Premier League after a wasteful Arsenal were made to pay at Vicarage Road.
Marco Silva’s side have now scored in the 90th minute or beyond in three consecutive games, as a second-half revival sealed their first home win of an impressive start to the campaign.
Arsene Wenger may well bemoan Troy Deeney’s second-half penalty, when Richarlison tumbled under debatable contact from Hector Bellerin, which let the Hornets level after Per Mertesacker gave Arsenal the lead before the break.
But without the rested Alexis Sanchez the Gunners lacked the cutting edge to capitalise on a string of chances, with substitute Mesut Ozil – also benched after his World Cup qualifying exertions for Germany in the week – guilty of one glaring miss.
Watford grew in confidence after the break and created their own opportunities. Brazilian striker Richarlison fired narrowly wide and after Silva brought Deeney off the bench, with the captain striking the post with a deflected attempt that could have sealed their win on 81 minutes.
Home comfort return for ambitious Silva
When Marco Silva arrived at Vicarage Road his record in home games was a key strength.
Silva had won many admirers with the way he slowed Hull City’s seemingly inevitable descent into relegation last term, even if he could not keep them up.
But seven games into his Premier League tenure at Watford, it was on the road where his resilient side were making their mark.
All of their wins had come away from Hertfordshire until Saturday, but the optimistic Portuguese may have sensed his luck could change against an Arsenal side without talisman Alexis Sanchez and struggling away from the Emirates.
When your side keeps playing for you until the last, you can even afford to be bullish about a zonal marking system that at one point seemed to cause more harm than good. Arsenal threatened from every set-piece as 5ft 9in Tom Cleverley seemed to be marking 6ft 6in Mertesacker.
It let the visitors open the scoring and remained a problem, but afterwards Silva stood by his methods.
“It’s not wrong,” he said. “It’s my decision and we will continue this way. We need to do more but we are strong zonally.”
After taking Watford into the Champions League places on a tiny fraction of the budgets elsewhere in the top four, few can argue.
Flaky Arsenal still lack nerve
Arsene Wenger has a ready-made excuse for his side’s latest set-back.
The penalty which allowed Watford back into this game was highly dubious. Former top-flight official-turned-analyst Graham Poll disputed it, as did the unfortunate Hector Bellerin who appeared to make no contact with Richarlison.
“A scandalous decision,” said Wenger. “But what can you do?”
Arsenal fans might be more concerned with the evidence that their side remain so defensively vulnerable.
Granted they had to ask injury-ravaged elder statesman Per Mertesacker to replace his sidelined compatriot Shkodran Mustafi here, but that was not solely to blame.
For 45 minutes at least the 33-year-old German was commanding on his first top-flight start since April 2016.
But worryingly for Arsenal in this contest, they faced only three shots on target and conceded twice.
The panic was palpable in their re-jigged back-line as Watford cranked up that trademark late pressure.
Wenger had readied Jack Wilshire from the bench but brought on another defender, Rob Holding, to hold onto a point. It wasn’t enough.
Not for the first time his defence switched off under pressure, leaving Cleverley unmarked to smash in the late heart-breaker.
Injuries can’t be helped. Organisation and calm under pressure are another thing.