Brighton and Hove Albion brought Arsenal's perfect start to the season to an abrupt end with a stunning 3-0 demolition of the Premier League champions on the south coast on Saturday.
Pascal Gross and Charalampos Kostoulas rewarded Brighton's first-half dominance with precise finishes and Chema Andres struck with a header after the interval as Arsenal slumped to their heaviest defeat for three years.
Earlier, Tottenham Hotspur scored their first Premier League goals of the season, but they proved in vain as they remained without a victory, going down 3-2 at home to Aston Villa.
Promoted Hull City suffered their first league defeat of the season as they lost 2-1 at Newcastle United while Everton moved into the top five as they beat Ipswich Town 1-0.
Coventry City scored their first goal and earned their first points since ending their 25-year exile from the top flight with a 1-0 win at Nottingham Forest to move off the bottom.
Arsenal had won seven successive matches since the start of the campaign, including their opening four Premier League games, to begin their title defense in ominous fashion.
But the wheels fell off spectacularly against a free-scoring Brighton side who moved into third place.
'NOT RESPECTING THE GAME'
"A really disappointing result and performance. Brighton were another gear up from us. We were extremely poor technically and not respecting the game," Arsenal manager Mikel Arteta said.
"They were another gear from us in the basics of the game."
Wearing a special blue-shirted kit to mark their 125th anniversary, Fabian Huerzeler's Brighton produced an intensity that Arsenal simply could not match.
Gross beat Arsenal keeper David Raya in the 31st minute with a low shot that went in off the upright -- his fourth goal in his last five games -- and Kostoulas scored with a similar effort following a counter-attack less than a minute after Bukayo Saka was close to an equalizer at the other end.
Andres punished some slack marking to head in from close range from Gross's corner.
Arsenal have 12 points from five games, the same as Manchester City who can move three points clear at the top if they beat Sunderland on Sunday. Brighton, who have scored a league-leading 16 goals, have 10 points.
TOTTENHAM LURCH DEEPER INTO TROUBLE
Aston Villa breathed a sigh of relief as they claimed their first league win of the season, but Tottenham's season lurched deeper into trouble after a third league defeat of the season.
Villa keeper Zion Suzuki produced several fine saves to frustrate Tottenham and Unai Emery's side took the lead in first-half stoppage time when summer signing Johan Manzambi tapped in while the hosts were down to 10 men after Micky van de Ven was off the pitch receiving treatment for a cut face.
Nicolas Jackson doubled Villa's advantage in the 67th minute, finishing clinically to put the visitors firmly in control and Emi Buendia struck 11 minutes from time with a rocket to the top corner from 22 yards.
Many Tottenham fans had streamed to the exits before Conor Gallagher and Jan Paul van Hecke scored late on to salvage some respectability for Roberto De Zerbi's strugglers.
"Today I was very disappointed, very sad, very frustrated for the performance. Because we can't lose this game in this way, absolutely," De Zerbi, whose side have two points and could end up bottom heading into the international break, said.
Thierno Barry's goal was enough for unbeaten Everton to take the points against Ipswich and move fifth. Abdul Fatawu was sent off for a second yellow card for Ipswich in the 67th minute.
Newcastle galloped into a two-goal lead against Hull with Joe Willock and Lewis Hall scoring in the opening seven minutes but were forced to hang on as Mohamed-Ali Cho replied for the visitors midway through the second half.
In the late game at the City Ground, Jay Dasilva's brilliant 55th-minute effort was enough for Coventry to make their mark after a tough start to the season for Frank Lampard's team.
Dasilva latched on to a long clearance and curled a shot past Matz Sels. Forest were denied a late equalizer when Igor Jesus poked home but was adjudged, after a VAR check, to have tripped defender Caleb Yirenkyi in the build-up.
