George Puscas hit the winner to maintain Reading’s 100% league record and end Watford’s unbeaten start.
Tom Holmes threaded a neat pass into Puscas, whose turn and shot deflected off Craig Cathcart and past the wrong-footed Ben Foster.
James Garner came closest for the Hornets, thundering a first-half free-kick against the crossbar.
Watford bossed the second half, but the hosts came closest to the game’s second goal when Foster saved Yakou Meite’s low drive and stay second, behind leaders Bristol City on goals scored.
The Reading defence, marshalled by Michael Morrison, have conceded just once in their four league wins to ensure the club’s best start since the 1985-86 season rolled on.
The Hornets were unbeaten in their previous six visits to Madejski Stadium, but their failure to turn chances into goals means their search continues for a first away win since January.
The injury-hit hosts gave starts to four academy players, with a further five on the bench alongside leading scorer Lucas Joao, and the Hornets were immediately on the front foot, with Ismaila Sarr’s pace tormenting the Reading defence.
Tom Dele-Bashiru had a header blocked, while Jeremy Ngakia dragged a shot wide and Sarr hit the side netting, all in the first 10 minutes.
But Watford have scored just twice in the Championship this season, and were punished for their lack of cutting edge as they conceded their first league goal of the season moments after Foster had saved well from Meite.
The visitors brought on Glenn Murray late on as they sought to turn their second-half dominance into an equaliser, but the Royals were content to play on the counter-attack and defended with discipline to stay second behind Bristol City.
Watford boss Vladimir Ivic told BBC Three Counties:
“I am disappointed because I believe we were the better team.
“We tried to react in the second half, we played organised for the first 15-20 minutes, maybe we didn’t create a clear chance, but in the last 20 minutes we start to be nervous, we start to lose the confidence, our shape and our movement.
“I can be satisfied with most of the game, we played good, especially in the first 45 minutes I believe we were dominant. We created three or four very good chances to score two or three goals.”
- 33Cabral Barbosa
- 3RichardsBooked at 62mins
- 28LaurentBooked at 39mins
- 24AlukoSubstituted forTetekat 84′minutesBooked at 87mins
- 7OliseSubstituted forMcIntyreat 61′minutes
- 18Lucas João
- 6WilmotBooked at 40mins
- 14ChalobahBooked at 90mins
- 24Dele-BashiruSubstituted forSemaat 37′minutes
- 21FemeníaSubstituted forCleverleyat 69′minutes
- 23SarrSubstituted forMurrayat 82′minutes
- 10João PedroBooked at 87mins
Match ends, Reading 1, Watford 0.
Second Half ends, Reading 1, Watford 0.
Hand ball by Craig Cathcart (Watford).
Foul by Glenn Murray (Watford).
Omar Richards (Reading) wins a free kick in the defensive half.
Nathaniel Chalobah (Watford) is shown the yellow card for a bad foul.
Foul by Nathaniel Chalobah (Watford).
Andy Rinomhota (Reading) wins a free kick in the defensive half.
Attempt missed. Dejan Tetek (Reading) left footed shot from more than 40 yards on the left wing misses to the left.
Attempt blocked. James Garner (Watford) right footed shot from outside the box is blocked.
Attempt missed. George Puscas (Reading) right footed shot from outside the box misses to the left. Assisted by Dejan Tetek.
João Pedro (Watford) is shown the yellow card.
Dejan Tetek (Reading) is shown the yellow card.
Nathaniel Chalobah (Watford) wins a free kick in the defensive half.
Foul by Dejan Tetek (Reading).
Substitution, Reading. Dejan Tetek replaces Sone Aluko because of an injury.
Substitution, Watford. Glenn Murray replaces Ismaila Sarr.
Foul by Ben Wilmot (Watford).
Michael Morrison (Reading) wins a free kick in the defensive half.
Corner, Watford. Conceded by Andy Rinomhota.