Arsenal show at Athletic that they possess the depth to win the Champions League

BILBAO, Spain -- It took just 36 seconds for Gabriel Martinelli to justify Mikel Arteta's belief that Arsenal now possess the squad to win the UEFA Champions League. After 70 minutes of toil against Athletic Club in Spain, Martinelli's instant impact as a match-winning substitute proved that Arteta now has game-changers on and off the pitch.

Martinelli's goal, 36 seconds after replacing Eberechi Eze, came from a pass by Leandro Trossard, who had only entered the game himself six minutes earlier in place of Viktor Gyökeres. Fifteen minutes later, Martinelli then turned creator for Trossard to score Arsenal's second to cap a 2-0 victory against Ernesto Valverde's team in Bilbao and set the Gunners on their way to a winning start in the League Stage.

Twenty-four hours earlier, addressing the media in his pre-match news conference, Arteta spoke of learning from last season's near miss. He said that the club's £300 million summer recruitment drive had given him a squad that was strong enough and deep enough to challenge for a trophy that Arsenal have never previously won.

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So when two substitutes enter the action and proceed to win the game, it says everything about the quality that Arsenal have now assembled for their manager.

"Sometimes the finishers will be more important than the starters this season," Arteta told reporters after the match. "And in the end, the finishers made the impact to win the game. [The substitutes] are at least equally important, and maybe more important, in that stage of games.

"I adore [Martinelli]. His attitude, his commitment, his positivity, what he's willing to do for the team. I don't know about externally, but we certainly value all the qualities that he has and that he brings to the team, and I'm so happy that today he decided the game.

"When I looked on the bench and looked at him, in his eyes I could see that he was ready, [Trossard] as well. They play with that confidence and that connection between them as well and really good. I think that's going to help us a lot this season."

When Arsenal's Champions League adventure came to an end last season, with a 2-1 defeat away to Paris Saint-Germain that sealed a 3-1 aggregate semifinal exit, Arteta's bench included the likes of Kieran Tierney, Oleksandr Zinchenko, Jorginho and Raheem Sterling -- all of whom are no longer at the club -- and untested youngsters such as Tommy Setford, Nathan Butler-Oyedeji and Jack Henry-Francis. Arteta used Trossard, Ben White and Riccardo Calafiori from the bench that night in the Parc des Princes, but the rest of his options were simply not up to scratch in terms of making the difference against Luis Enrique's side.

It is a different story this season. The summer spending has brought Gyökeres, Eze, Noni Madueke, Martín Zubimendi, Cristhian Mosquera, Piero Hincapié and Christian Nørgaard to the Emirates, and they all featured at Estadio de San Mamés on Tuesday.

But Arteta's bench also included William Saliba, Ethan Nwaneri, Myles Lewis-Skelly, Kepa Arrizabalaga and 15-year-old wonderkid Max Dowman as unused subs. The strength in depth is formidable, and it has taken Arsenal to another level.

Yes, there is still no obvious replacement or cover for injured captain Martin Ødegaard, whose shoulder problem forced him to miss the trip to Bilbao, but Arteta now has perhaps 20 players he can trust and rely upon to perform against any opponent. And in the Champions League, options on the bench matter.

The history of the competition is littered with examples of teams winning because of their substitutes, dating back to Teddy Sheringham and Ole Gunnar Solskjaer both scoring late goals as subs in Manchester United's 1999 final win against Bayern Munich. Divock Origi made a huge contribution to Liverpool's success in 2019, often scoring as a substitute for Jürgen Klopp's team, while Real Madrid have turned to the likes of Rodrygo, Marco Asensio, Álvaro Morata and even Joselu during their recent years of success.

If Arsenal are to win the Champions League, Arteta at least knows that he now has players who can be his Origi, Solskjaer or Rodrygo. But he will also need his big guns back -- crucial players such as Ødegaard, Bukayo Saka and Kai Havertz, whose pedigree in this competition saw him score the winning goal for Chelsea in their 2021 final win against Manchester City.

Beating Athletic Club on Matchday 1 is unlikely to be a hugely significant result if Arsenal go all the way this year, but the way that they achieved it will resonate. Not only do Arsenal know that they can win games from the bench, but so will their future opponents, and it can be a psychological advantage to have a group of players who can be decisive finishers if the starters fail to make the breakthrough.