The Gunners conceded three first-half goals during an uncharacteristically sloppy defensive performance.

Despite having less possession, the Spanish side were more threatening throughout and had more shots on target than Arteta's men.

When asked what the mood in the dressing room was like after their first-half display, the Arsenal boss said: "Very upset, given a hard time. They are fuming, but this is good. That's what we need."

The Gunners are still without Declan Rice, Eberechi Eze, Noni Madueke and Bukayo Saka, who have still not joined up with the squad following their World Cup campaign with England.

While Spain's World Cup winners Mikel Merino, David Raya and Martin Zubimendi are also yet to return, captain Martin Odegaard has resumed individual training after featuring for Norway in the tournament.

But despite those key players not being available, their starting XI against Betis included four international defenders, as well as Ethan Nwaneri, Kai Havertz, summer signing Christos Tzolis and Max Dowman in midfield, with Viktor Gyokeres leading the line.

While unhappy with Arsenal's performance, Arteta hoped the defeat would spur them to improve.

"Well, the important part is to win it and we didn't manage to win it, so disappointed obviously for the result," he added.

"It's true we used 25 players, so you need to give a bit of context to the game.

"In the first half, with more starters, two very different things: how we played and how we competed, because we had some fantastic moments in the time we played.

"The way we competed especially in and around our box in a number of standards that we are used to, so there are things to improve obviously, some positives to take from the game and then a bad result sometimes it's good to create even more fire in the belly."

Arteta named the same side that had beaten Girona 4-1 last week in Spain, but they made mistakes at the back and lacked the same attacking spark despite a line-up packed with talent and experience at both ends of the pitch.

Arsenal controlled possession at the start and Gyokeres had a great opportunity to open the scoring, but was denied by the outstretched boot of Alvaro Valles.

But the Gunners fell behind following a ninth-minute corner - a situation where they pride themselves on defending well.

Second-choice goalkeeper Kepa Arrizabalaga misjudged the flight of the set-piece by Pablo Fornals and got stuck underneath the cross as it dropped to an unmarked Rodrigo Riquelme to slam in a finish at the back post.

Myles Lewis-Skelly, who ended the season so well in the title run-in, was at the base of the Arsenal midfield and one of their better performers.

He also had the task of filling in for left-back Riccardo Calafiori when the Italian went on one of his roaming runs in attacking areas, often finding himself in pockets of space behind the Arsenal frontline.

Greece winger Tzolis, who scored against Girona and played on the same side as Calafiori, had a chance to equalise after intercepting a loose pass from keeper Valles, but poked the ball wide and failed to hit the target.

That was the story of the match against a lively Real Betis side managed by former Manchester City boss Manuel Pellegrini and who will be in this season's Champions League after a 20-year absence.

Arsenal were punished by two more errors either side of a Piero Hincapie goal in the 32nd minute, with the defender heading in a Tzolis corner after Valles failed to deal with the set-piece.

First Nelson Deossa scored with a superb 26th-minute strike, firing into the top corner from around 25 yards following a poor Kepa clearance.

Former West Ham midfielder Fornals then rolled the ball into the corner from the edge of the area in the 43rd minute, past a helpless Kepa after Havertz misplaced a pass around the edge of the Arsenal box.

Arteta made seven changes at half-time, which included the first minutes of pre-season for Gabriel Martinelli and Gabriel Magalhaes who returned to club action after representing Brazil at the World Cup.

Defender Marli Salmon, 16, and 19-year-old Louie Copley were two of those changes, but midfielder Copley was withdrawn just seven minutes after making his entrance when he suffered a knee injury after landing awkwardly when chasing a ball.

As is often the case with pre-season friendlies, more substitutions meant the game lost its flow and despite Gabriel Jesus going relatively close with an effort in the second half, Arsenal never looked like clawing back the deficit as Arteta cut a frustrated figure on the touchline.