Watford came from two goals down to beat West Ham United 4-2 at London Stadium this afternoon.
The Hornets secured all three points despite falling two goals behind inside the first half.
Two Michail Antonio headers looked to have put the hosts on course to win, but Troy Deeney and Odion Ighalo both scored as half-time approached.
Further goals in the second-half from Etienne Capoue and Jose Holebas ensured the Hornets returned home with their first win of the season.
Walter Mazzarri made four changes to the side that faced Arsenal two weeks previously. Roberto Pereyra made his full debut in place of Adlene Guedioura, and Daryl Janmaat came in to replace Nordin Amrabat.
Defenders Miguel Britos and Craig Cathcart returned to the starting XI, replacing Christian Kabasele and Sebastian Prödl.
The Hammers got off to an electric start as both Antonio and Dimitri Payet forced Heurelho Gomes into action inside the opening two minutes of the match.
Valon Behrami played Ighalo in over the top down the left-flank. The front-man knocked the ball past James Collins but his low effort at goal skimmed the side-netting.
But a minute later the Hammers were ahead. Payet's in-swinging corner from the left was met by Antonio inside the box and the front-man made no mistake, guiding his header into the bottom corner past Gomes.
The scores should have been level as Pereyra darted down the left before squaring the ball to Ighalo in-front of goal, but the front-man dwelled on it for too long and Arthur Masuaku was able to knock clear.
Lanzini raced through the middle of the pitch but his long-range effort bounced wide of Gomes' goal.
West Ham's shot-stopper Adrian was called into action following some impressive play by Pereyra. He beat Payet down the right before cutting the ball back to Ighalo. The front-man met it on the volley but saw his effort well saved.
Lanzini and Zaza combined efficiently midway through the half, but the former's cheeky effort at goal went wide.
The hosts extended their lead past the half-hour mark as Payet chipped a fantastic ball in from the right which was met by Antonio. The wide-man dived in to head home his second of the afternoon.
However the game took a swing in the Hornets' favour during a five-minute period as half-time approached.
Capoue clipped a great ball over the top to Ighalo who weaved his way past Sam Byram. He twisted the ball onto his right-foot before firing into the back of the net via a Collins deflection.
And the scores were level on the stroke of half-time in spectacular fashion through skipper Deeney.
Kaboul's long clearance was headed away from Adrian by Collins. Deeney nipped in before turning and curling the ball into the top corner from the tightest of angles with fantastic precision.
West Ham fashioned two half-chances early on in the second-half but neither effort tested Gomes.
The Hornets too were getting forward well as Ighalo fired an effort wide from distance.
Holebas' ball in from the left caused the hosts all sorts of problems. Winston Reid's low headed clearance only just went wide of the post.
The Hornets were ahead for the first time in the game just moments later with another spectacular finish. Pereyra's cross from the right reached the unmarked Capoue. The midfielder brought the ball down before thrashing a half-volley into the top corner for his third of the season.
Collins almost made amends for his earlier mistakes as he met Byram's ball into the box, but his header went wide.
Mazzarri's men were looking extremely efficient in attack and were well worth their lead. Janmaat almost extended the score but saw his shot well blocked by Reid inside the box.
However only a minute later the Hornets had their fourth and final goal of the afternoon. Ighalo weaved his way down the left before cutting the ball back to Holebas who curled in a first-time effort via the glove of Adrian.
The first change of the afternoon came with 68 minutes played as Isaac Success came on in place of goal-scorer Ighalo, who had made a telling contribution for the Hornets.
Success made an instant impact, racing clear and nudging the ball past Collins before seeing his low strike saved by Adrian.
Stefano Okaka was the second change of the afternoon as he came on in place of Deeney upfront.
It was all Watford as Pereyra avoided a number of challenges before seeing his shot saved by Adrian.
The Hornets thought they had a fifth, but substitute Okaka was denied by the assistant's flag as he tapped in Kaboul's knock-down from a corner.
With his final change of the afternoon, Mazzarri brought on Sebastian Prödl in place of Kaboul at the heart of the Watford defence.
The Hornets continued to attack and substitutes Okaka and Success linked up well as the former's shot was held by Adrian.
As full-time approached Okaka was forced off through injury, meaning the Hornets ended the game with ten-men.
The four minutes of injury time were negotiated with ease and the Hornets went on to record their first three points of the Premier League season.
WATFORD: Gomes (GK); Cathcart, Kaboul (Prödl, 81), Britos; Janmaat, Capoue, Pereyra, Behrami, Holebas; Deeney (c) (Okaka, 78), Ighalo (Success, 68).
Subs not used: Pantilimon (GK), Zuniga, Watson, Guedioura.
Goals: Ighalo (41), Deeney (45), Capoue (53), Holebas (63)
Yellow Cards: Cathcart (42), Okaka (86)
WEST HAM: Adrian (GK); Byram (Töre, 85), Collins, Reid, Masuaku; Noble (c) (Calleri, 68), Kouyate; Antonio, Lanzini, Payet; Zaza (Fletcher, 77).
Subs not used: Randolph (GK), Nordtveit, Obiang, Ogbonna.
Goals: Antonio (5, 30)
Yellow Cards: Zaza (12), Byram (85)
Attendance: 56, 974
Match report by Ed Henderson