Chelsea ended Sunday’s 2-1 defeat by champions Arsenal with two players who began their careers as right-backs alongside each other in midfield.

After spending £349m during the summer transfer window, how did they reach that point?

It was Reece James, who began his career as a right-back, who failed to track captain Martin Odegaard as he scored Arsenal‘s winner at Emirates Stadium.

In the build-up to his first defeat as Chelsea manager, Xabi Alonso said he believes James can become one of the best midfielders in the world.

James performed well otherwise and spent almost half of last season playing in midfield.

But there are legitimate questions about Chelsea‘s depth in that area after Malo Gusto replaced midfielder Romeo Lavia in the second half.

It was lax marking that led to Odegaard’s winner, while a lack of creativity from the bench left Chelsea short as Arsenal boss Mikel Arteta’s substitutes ultimately helped guide the hosts to victory.

“Chelsea don’t have European football this season so they’re playing less games and can concentrate on the Premier League. But the worry is you’re finishing a game against the champions, and you’ve got two right-backs in midfield,” Ashley Young told BBC Sport.

“You look at Lavia, who was injured a lot last season. The front line are going to send fear throughout the league but behind that you see the midfield and they’re playing right-backs there.

“Teams will be seeing the game today, seeing that Chelsea will sit in there and get men behind the ball, but there’s still spaces through the lines, and Arsenal found that out.

“Chelsea are giving up a lot of possession and they’re playing counter-attacking football. Today there was probably only once with [Pedro] Neto down the right side when they capitalised on the counter.”

The primary issue is the absence of midfielder Moises Caicedo.

The Ecuador international is out with an unspecified injury for an unknown period after breaking down just 11 minutes into a substitute appearance against Brighton last week.

It has left Alonso in almost uncharted territory for a Chelsea boss. Aside from suspensions, Caicedo had missed only two matches during the previous three seasons, through a knock and illness.

Asked about Caicedo, Alonso said: “Not longer term, but it is about assessing the risk. Probably last week we brought him back too early and I don’t want to make the same mistake again.”

It remains unclear whether Chelsea had concerns over Caicedo’s fitness while pursuing several central midfielders on transfer deadline day.

Monaco pulled the plug on Chelsea‘s £47m move for Lamine Camara at the last minute, leaving officials at Stamford Bridge furious.

Chelsea also had bids of up to £64m rejected for Bournemouth‘s Alex Scott earlier in the summer and were prevented from signing France international Manu Kone after Roma head coach Gian Piero Gasperini blocked the move.

Chelsea said they pursued Camara because of a market opportunity, adding that they were satisfied with their summer business and retained faith in their current options.

That was despite selling Enzo Fernandez to Manchester City for a joint British-record fee of £125m on deadline day, without signing a direct replacement.

However, Caicedo’s absence means he joins Jordan Henderson on the sidelines, with the England international still recovering from a broken arm suffered after falling over an advertising hoarding while an unused substitute at the World Cup.

Natural midfielder Valentin Barco, who joined from Strasbourg in the summer, has been overlooked in favour of Gusto in all three of Chelsea‘s Premier League matches.

With Gusto starting in midfield, Chelsea recorded 25.6% possession in last weekend’s 4-3 victory over Brighton, their lowest figure since records began in 2003-04.

If all of Chelsea‘s midfield options are fit, and Caicedo’s injury proves only minor, they should be able to cope with five midfielders in a season without midweek European football, as Alonso argued before the match.

Chelsea have leaned on their star attackers in Morgan Rogers, a resurgent Cole Palmer and the prolific Joao Pedro in their opening three matches.

Yet having conceded seven goals in three matches, Alonso said “we want to be tighter”.

There was still plenty to admire about Chelsea‘s performance.

Club-record signing Rogers scored again in the second minute, becoming the first Chelsea player to score or assist in each of the club’s opening three Premier League matches of a season since Eden Hazard in 2018-19.

It was arguably one of Chelsea‘s better performances against Arsenal during a run of 10 matches without a win against their London rivals.

There remains a 33-point gap to make up after Chelsea finished 10th in the Premier League last season.

Alonso said after the match: “We came to win. We knew that we were not that far, but it went their way.

“It hurts, [we’re] disappointed for sure. But this is the first defeat, this is going to be a long way and it doesn’t have a big impact in our mood and in our mindset.”

Arsenal remain the benchmark Chelsea are trying to reach. Although the Blues beat them to the signing of Rogers, they still trail the standard-setters in London and the Premier League.

It served to highlight that, despite already recruiting 10 first-team players during a busy summer, Chelsea‘s failure to sign a midfielder on deadline day may have left them with a potential weakness.

Alonso described the summer as “phase one” earlier this week. If Caicedo’s return does not resolve Chelsea‘s midfield issues, the club may face questions over its decision not to sign a replacement for Fernandez before turning back to the market in January.