Arsenal bounced back from Thursday's Europa League loss to PSV Eindhoven by returning to the top of the Premier League table with an emphatic win over Nottingham Forest.
Gabriel Martinelli headed the Gunners in front early on before England's Bukayo Saka - who set up the opener - was forced off with an injury.
Reiss Nelson, Saka's replacement, doubled the lead four minutes after the restart with his first Arsenal goal since November 2020 before quickly adding his second.
Thomas Partey and Martin Odegaard goals added gloss to the scoreline as Arsenal restored their two-point lead over Manchester City at the summit, with Forest still bottom after an eighth defeat of the season.
Arsenal run riot despite Saka injury
Saka was on the receiving end of Renan Lodi's heavy challenge in the opening minute, and while he recovered to tee up Martinelli, the 21-year-old twice required treatment before being taken off in the 27th minute.
The sight of Saka heading straight down to the tunnel after being substituted will concern England fans just three weeks out from the start of the World Cup.
While Saka looked bright before being withdrawn, Nelson seized an opportunity to shine on his first Premier League appearance since the opening match of last season.
Saka looked to be struggling after a robust challenge from Renan Lodi in the opening minuteThe 22-year-old, who spent the 2021-22 campaign on loan at Feyenoord, put daylight between the teams when he fired home at the second attempt after Dean Henderson saved his initial shot.
Having had to wait almost two years for an Arsenal goal, Nelson scored his second in the space of three minutes when he poked a Gabriel Jesus cross into the far corner.
Nelson then turned provider, teeing up Partey, who lashed a superb right-footed shot into Henderson's top corner before Odegaard hammered home a fifth to cap a dominant Arsenal display.
Forest collapse in second half
For Forest, it was a sobering defeat after the ecstasy of their shock win over Liverpool last week.
Sights of the Arsenal goal were rare for the visitors in the first half, with Remo Freuler firing a long-range shot straight at Aaron Ramsdale and Jesse Lingard seeing his effort blocked after Gabriel Magalhaes gifted him the ball.
Trailing by a single goal at the break, Forest boss Steve Cooper will be disappointed with how his side collapsed in the early stages of the second half.
However, with Forest having picked up just two points on the road this season, taking something away from Emirates Stadium was always going to be a big ask.
But they will look to regroup quickly with home games against Brentford and Crystal Palace before the season breaks for the World Cup.
Arsenal showed support for the club's defender Pablo Mari, who is recovering after being stabbed in an Italian supermarket on ThursdayhelpHow to play
Rate players out of 10 throughout or after the game. The rater will close 30 minutes after the final whistle.
Rating range key1 = Give it up10 = Pure perfection
Nottingham Forest
Squad number1Player nameHenderson
Squad number24Player nameAurier
Squad number3Player nameS Cook
Squad number26Player nameMcKenna
Squad number32Player nameRenan Lodi
Squad number22Player nameYates
Squad number23Player nameFreuler
Squad number21Player nameKouyaté
Squad number10Player nameGibbs-White
Squad number9Player nameAwoniyi
Squad number11Player nameLingard
Squad number4Player nameWorrall
Squad number7Player nameN Williams
Squad number14Player nameO'Brien
Squad number20Player nameJohnson
Squad number25Player nameDennis
Line-ups
Arsenal
Formation 4-3-3
1Ramsdale
4White12Saliba6Gabriel18Tomiyasu
8Ødegaard5Partey34Xhaka
7Saka9Gabriel Jesus11Martinelli
1Ramsdale4White12SalibaSubstituted forTierneyat 76'minutes6Gabriel18TomiyasuSubstituted forCédric Soaresat 63'minutes8Ødegaard5Partey34XhakaSubstituted forNketiahat 75'minutes7SakaSubstituted forNelsonat 27'minutes9Gabriel Jesus11MartinelliSubstituted forFábio Vieiraat 63'minutesSubstitutes
3Tierney14Nketiah16Holding17Cédric Soares21Fábio Vieira23Sambi Lokonga24Nelson27Marquinhos31HeinNottm Forest
Formation 4-3-3
1Henderson
24Aurier3S Cook26McKenna32Lodi
22Yates23Freuler21Kouyaté
10Gibbs-White9Awoniyi11Lingard
1Henderson24Aurier3S Cook26McKenna32LodiSubstituted forN Williamsat 64'minutes22Yates23Freuler21KouyatéSubstituted forO'Brienat 81'minutes10Gibbs-WhiteBooked at 44minsSubstituted forJohnsonat 56'minutes9AwoniyiSubstituted forWorrallat 64'minutes11LingardSubstituted forDennisat 56'minutesSubstitutes
4Worrall5Mangala7N Williams13Hennessey14O'Brien16Surridge20Johnson25Dennis30BolyReferee:Simon HooperAttendance:60,263Live Text
Match ends, Arsenal 5, Nottingham Forest 0.
Second Half ends, Arsenal 5, Nottingham Forest 0.
Attempt saved. Neco Williams (Nottingham Forest) right footed shot from outside the box is saved in the top centre of the goal. Assisted by Scott McKenna with a headed pass.
Corner, Nottingham Forest. Conceded by Cédric Soares.
Foul by Kieran Tierney (Arsenal).
Sèrge Aurier (Nottingham Forest) wins a free kick on the right wing.
Attempt missed. Thomas Partey (Arsenal) right footed shot from outside the box is high and wide to the right.
Attempt blocked. Gabriel Jesus (Arsenal) right footed shot from outside the box is blocked. Assisted by Eddie Nketiah.
Attempt blocked. Fábio Vieira (Arsenal) left footed shot from the centre of the box is blocked. Assisted by Reiss Nelson.
Foul by Cédric Soares (Arsenal).
Neco Williams (Nottingham Forest) wins a free kick in the defensive half.
Attempt missed. Ben White (Arsenal) header from the centre of the box is close, but misses to the left. Assisted by Martin Ødegaard with a cross following a corner.
Corner, Arsenal. Conceded by Neco Williams.
Substitution, Nottingham Forest. Lewis O'Brien replaces Cheikhou Kouyaté.
Corner, Nottingham Forest. Conceded by Kieran Tierney.
Corner, Nottingham Forest. Conceded by Cédric Soares.
Goal! Arsenal 5, Nottingham Forest 0. Martin Ødegaard (Arsenal) left footed shot from the centre of the box to the top left corner. Assisted by Gabriel Jesus.
Offside, Nottingham Forest. Dean Henderson tries a through ball, but Ryan Yates is caught offside.
Foul by Fábio Vieira (Arsenal).
Ryan Yates (Nottingham Forest) wins a free kick on the right wing.
Our coverage of your Premier League club is bigger and better than ever before - here's everything you need to know to make sure you never miss a moment