Pep Guardiola's Manchester City finally conquered their final hurdle in Istanbul.

For the overwhelming majority of Guardiola's stint in Manchester, the Cityzens were regarded as far too good not to win Europe's premier club competition. Yet, they continued to find new ways of failing.

Despite a valiant Inter effort in last season's showpiece event, there was an air of inevitability surrounding City's treble triumph, which Rodri's strike secured. The one-time Champions League winners are once again favoured to go all the way in Europe this season - with their chances boosted by a kind group stage draw - but who are their biggest challengers?

Here's who Opta rate as the top contenders for Man City's Champions League crown.

9. Atletico Madrid (2.4% chance of winning the UCL)

Once a formidable Champions League outfit, Atletico Madrid have disappointed on the grandest stage in recent times. They finished bottom of their group last season, but there's hope Diego Simeone can oversee an improved campaign this time around.

They've been placed into a group which they should win and the early signs this term are hugely promising. They're playing with a swagger.

However, the swashbuckling iteration of Los Rojiblancos that shows up in La Liga often turns into a bitty, petulant and stodgy outfit on European nights.

8. Barcelona (3.2% chance)

Barcelona have been nothing short of woeful in Europe since Xavi took charge which is why Opta currently give La Blaugrana a 3.2% chance of winning the competition despite their La Liga success last time out.

They haven't qualified for the Champions League knockouts since 2020/21, although they have been dealt some very tough groups.

That isn't the case this time around. Barcelona should coast Group H, but nothing is simple in Europe for Xavi's Blaugrana.

7. Manchester United (3.3% chance)

Many questions surround Erik ten Hag's Man Utd at the start of 2023/24. We don't know what they are, and it appears as if they're going to be very reliant on an inexperienced 20-year-old forward to enjoy a marked improvement this season.

United will have to improve swiftly because their Champions League group could swallow them up. Bayern's prowess is obvious and an away trip to Galatasaray isn't for the faint-hearted.

Ten Hag had some success in this competition with Ajax in 2018/19 and 2020/21, but it's been a while since United were a major player in the Champions League.

6. RB Leipzig (3.8% chance)

Opta are confident RB Leipzig will escape Group G alongside Man City.

Marco Rose's side laid down a marker before the season got underway when they thumped Bayern in the DFL-Supercup and they've started the Bundesliga campaign in majestic form.

They invested shrewdly in the summer and while questions may arise about their defensive strength against the very best opposition, Leipzig boast an attack capable of striking fear into any opponent. Xavi Simons is poised to embark on a breakout Champions League campaign, while Benjamin Sesko is surely just a few games away from being linked with Chelsea.

5. Napoli (4.5% chance)

Napoli's Champions League dream was dashed by a familiar foe in the last eight last season as their Scudetto charge eventually caught up with them. They were outwitted by Milan over two legs.

The exits of Luciano Spalletti and Kim Min-jae render Napoli weaker compared to last season and it is somewhat of a surprise that they're this high up on the list of contenders.

However, perhaps they'll place more emphasis on this competition during the latter stages now they've got a league title in their back pocket.

4. Inter (5.6% chance)

Beaten finalists last time out, Inter have developed into a stellar cup team under Simone Inzaghi. The Nerazzurri have won back-to-back Coppa Italia titles and Supercoppas with the former Lazio boss at the helm.

They step up when it matters most.

At the start of 2023/24, Inter look like the best side in Italy with Lautaro Martinez and Marcus Thuram potentially recreating the devastating 'LuLa' connection of the Antonio Conte era.

The Nerazzurri are efficient in all phases and showed in last season's final they're capable of competing with any side that pitches up in front of them.

3. Real Madrid (6.0% chance)

There was no voodoo magic for Real Madrid to lean on in the semi-finals last season as they were battered at the Etihad.

The Cityzens were a class above, but you can expect Los Blancos to come back firing in 2023/24.

It was a summer of change for the club as Karim Benzema departed, but their core has largely remained intact with Jude Bellingham providing a Galactico presence in midfield.

Carlo Ancelotti's side are always going to be a contender given their pedigree, but they'll likely need Thibaut Courtois fit for the latter stages of the competition if they're to usurp City.

2. Arsenal (8.7% chance)

Returning to the competition for the first time in six years, Arsenal are Opta's third favourites to win the Champions League.

Mikel Arteta's project boomed last season as they challenged City for the Premier League title and while they haven't pitted their wits against Europe's best for a while, it's hard to argue against the notion of them being one of the finest sides the continent has to offer.

They were dealt a tame group they should coast, but inexperience and a lack of depth in key areas could compromise Arteta's men during the latter stages.

1. Bayern Munich (10.9% chance)

While simmering discontent is present within the Bayern camp, Harry Kane's arrival renders Thomas Tuchel's side a major threat to City's crown.

Bereft of a reliable goalscorer last season, Bayern were never a serious contender for Europe's most prestigious prize and were swatted aside by City on their way to glory.

Their acquisition of Kane solved a distinct need in the biggest way, but concerns remain in midfield. Had they scooped up Joao Palhinha from Fulham on deadline day, their chances of UCL success would've been further emboldened.

Question marks still surround Tuchel's Bayern, but the significance of Kane's presence can't be overlooked. He'll be determined to shine on the biggest nights.

Opta's favourities for the 2023/24 Champions League

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This article was originally published on 90min as Supercomputer predicts Man City's biggest challengers in 2023/24 Champions League.