Norwich City fell to a 4-0 defeat away at Arsenal on Wednesday evening.
First half goals from Pierre-Emerick Aubameyang and Granit Xhaka put the Gunners in control at the interval, but City rallied early in the second-half to threaten a comeback.
However, Aubameyang capitalised on a defensive error and substitute Cedric Soares fired a deflected effort home to see Arsenal run out 4-0 winners.
Daniel Farke made just one change to his starting eleven from Saturday's FA Cup defeat to Manchester United with Tom Trybull replacing the suspended Timm Klose. Alex Tettey moved into the back four with Trybull anchoring the midfield.
There was a spot for young Jordan Thomas on the bench, the Under-23s right-back enjoying his first involvement in a senior matchday squad.
The first piece of action came from Arsenal with Hector Bellerin making a clever run behind Jamal Lewis inside the opening ten minutes. However, Alex Tettey covered his defensive partner well to block and win a goal-kick.
Shortly after, Arsenal threatened once more. A three-v-one on their left saw Aubameyang coast into the area and force Krul into a smart save.
Arsenal continued to dominate the opening stages and Aubameyang met a Bellerin cross but could only head straight at Krul before a rare foray into the Arsenal half from Ben Godfrey almost brought a City opener on 21 minutes. Godfrey took aim from 30 yards and saw his rising drive clip the post with Emiliano Martinez at full stretch.
City found it difficult to get the ball forward in the opening half an hour and they gifted the home side an opener on 32 minutes when Krul was dispossessed in his own box, allowing Aubameyang to slot into an empty net.
Minutes later, it was two for Arsenal. Granit Xhaka ghosted into the area and got on the end of a low Aubameyang cutback to fire underneath Krul.
There was almost cause for optimism at just before half-time for City when Kenny McLean sent a free-kick from distance towards the top corner, however Martinez made a super save to his left.
Farke made three changes for the second-half with Onel Hernandez, Josip Drmic and Adam Idah all introduced and the latter was instantly involved, forcing Martinez into a save low to his left.
The encouraging signs continued for City as Hernandez got in on the act on 53 minutes, cutting inside from the left and shooting narrowly over from distance.
Their hopes were dashed with around 25 minutes to play when a loose Drmic pass allowed Aubameyang with a free path at goal and his slotted past Krul for his second of the game.
The game was put beyond any doubt on 81 minutes when substitute Cedric fired a deflected effort into the bottom corner after City failed to clear a set-piece.
Arsenal: Martinez, Mustafi (Holding, 46), David Luiz, Kolasinac, Bellerin (Cedric, 76_, Xhaka, Ceballos, Tierney, Nelson (Willock, 57), Aubameyang (c) (Pepe, 82), Lacazette (Nketiah, 75)
Subs not used: Macey (GK), Sokratis, Maitland-Niles, Saka
Goals: Aubameyang (32, 67), Xhaka (37), Cedric (81)
Bookings: Martinez (71)
Norwich: Krul (GK), Aarons, Godfrey, Rupp (Vrancic, 75), Lewis, Cantwell (Stiepermann, 75), Buendia (Hernandez, 46), Trybull (Idah, 46), Pukki (Drmic, 46), McLean, Tettey (c)
Subs not used: McGovern (GK), Duda, Thomas, Martin
Bookings: McLean (26), Rupp (30), Vrancic (86)
Venue: Emirates Stadium
Referee: Peter Bankes