Viktor Gyökeres showed the impact he can make this season, but after injuries to key players, Arsenal's depth might be tested immediately. Julian Finney/Getty Images

Part of the justification for Arsenal's £260 million spending spree was to add squad depth so they could avoid a repeat of last season's injury-ravaged campaign. Saturday's 5-0 demolition of Leeds United was a demonstration of the feel-good factor that outlay has created, but it also served as a warning that this deeper pool of options could be tested much sooner than the club hoped.

The positives at Emirates Stadium were numerous and began before a ball was kicked. Eberechi Eze was unveiled 15 minutes before the start as Arsenal's seventh summer signing after joining the club he supported as a boy from Crystal Palace for £67.5 million. Turning down north London rivals Tottenham in the process will only make him more of an instant hero.

Jurriën Timber scored the first and fourth goals by netting from set pieces, proving that rich supply line that has served this team so well in the past is still a potent threat. Make that 33 goals from corners since the start of the 2023-24 season. In between, Bukayo Saka thrashed a shot past Leeds goalkeeper Lucas Perri on the stroke of halftime before Viktor Gyökeres, the man of whom so much is expected at the focal point of Arsenal's attack, cut in from the left and fired a low shot into the net for his first Gunners goal.

Max Dowman became the club's second-youngest Premier League player ever, at 15 years and 234 days old, with a 26-minute cameo featuring a jinking run into the box that duped Leeds midfielder Anton Stach into treading on his foot to concede a penalty.

It was reminiscent of two matches in Arsenal's preseason -- against Newcastle and Villarreal -- when Dowman earned spot kicks with purposeful runs. Gyökeres emphatically dispatched the resulting penalty this time.

The young and the new have given Arsenal a genuine sense of reinvention. "Well done to everybody who was involved in that deal [for Eze]," said Mikel Arteta. "Because I think it started to create some flames, some fire in the stadium. That was great to witness.

"You could sense something, especially in the atmosphere already before the match. I think we have to be very proud of the way we played, the way we dominated the game."

Keeping a lid on the expectation around Dowman might prove extremely difficult if he continues doing this. "We have to gather all the information," Arteta said of Dowman. "It's how he reacts and deals with the situation. What his teammates think about him, which is clear, because they kept on passing him the ball.

"It is great to be able to change the energy in the stadium by bringing him in, and he had an impact. He won a penalty on his debut at the Emirates, that's incredible. He's so convinced that he can go at 15 and deliver that, which I've never witnessed in my life. And for us, it brings joy, it brings emotion and something else that makes our jobs so great."

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Yet there are issues on the horizon. Captain Martin Ødegaard went off with a shoulder problem on 38 minutes -- having tried to carry on for several minutes after suffering the initial problem -- while Saka also exited earlier, eight minutes into the second period with what appeared a more serious issue. Ben White and Christian Nørgaard are also currently sidelined. And with Kai Havertz set for a spell on the sideline after a knee injury, Arsenal suddenly face the prospect of fielding an entirely new forward line for their final game before the international break: defending champions Liverpool at Anfield.

It is, of course, too early to know the extent of the injuries, but there remains the potential for Gyökeres, Noni Madueke and perhaps Eze to start next weekend in what will stand as an early litmus test of Arsenal's resolve to challenge for the Premier League title.

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"Those [injuries] are the negatives of the day," said Arteta. "Martin felt something in his shoulder when he landed. We don't know. We'll have to scan him tomorrow and understand a bit better. And Bukayo, while he was running with the ball, carrying the ball, wrestling with the defender, he felt something in his hamstring. So let's see. I think it's the other [shoulder]. It's not the same one as the previous injury.

"But we are two weeks [into the season] and we already lost Kai, Martin and Bukayo. So it tells you how well-equipped you have to be in this league to manage and to maintain the level that we want."

Arteta later added to beIN SPORTS: "For Bukayo to come off, for sure it looks like something that is significant."

Gyökeres will head to Merseyside emboldened by this experience. A shaky early moment in which he snatched at a chance that suddenly came his way as Leeds botched an attempt to play out from the back reflected an indifferent first half. But his goal three minutes into the second period was a demonstration of the power he possesses -- albeit aided by some weak defending -- and was greeted by what appeared to be a cathartic release of energy as he put a slow start at Manchester United last weekend behind him.

His stoppage-time penalty was the icing on the cake at the end of the afternoon. "I know I'll take my chances sooner or later," Gyökeres said. "We won 5-0 so it was a great day.

"Of course, it was a short preseason for me and not too many weeks training, and then, of course, playing 90 minutes in preseason. It was important for me to get 90 minutes and get the rhythm and to get to know the team even more during this game. I felt more comfortable in how we're playing, and I think you can see that as well."

Sterner tests await, but Arsenal are hoping they will be better equipped for the challenge this time.

[Getting players in is what] we need," Arteta said. "I think the other way is not realistic, to survive at the levels that we want for 10 months. Because none of the other top teams in the league do it. So why are we going to be different? They still have even bigger squads than we have. So that's the minimum that we can have to compete and be able to do what we want."