Manchester City begin their defence of the Champions League on Tuesday when the group stage kicks off in the last season in its current format as Europe's elite club competition gets ready for a radical change.

Unveiled by UEFA in 2021 at the height of the crisis which saw a group of 12 clubs announce a breakaway Super League before promptly abandoning the project, the new-look Champions League will begin next year.

It will see the number of clubs involved in the competition proper increase from 32 to 36, with all participants going into a single league in which teams will play eight games -- up from the current six -- in what is known as the "Swiss system".

This is therefore the last campaign, after two decades, in which the Champions League will begin with a group stage featuring eight sections of four teams, with the top two in each advancing to the last 16.

It is hard to imagine Swiss side Young Boys or Serbia's Red Star Belgrade making a big impact alongside Pep Guardiola's City and RB Leipzig in Group G.

City should stroll through to the last 16, racking up goals in the process, and they begin as favourites to retain a trophy they won in June by beating Inter Milan 1-0 in the final in Istanbul.

Asked about City's chances of retaining the title, Guardiola told reporters: "It'll be easier. The most difficult to win is the first one. It is incredible for us but it is just one.

However, Guardiola said his players should not feel at ease, adding: "Tomorrow is the first step. We will try and get the first three points. It's important the players don't feel relaxed."

So who can stop a strong and confident City this time around?

It probably will not be the champions of Switzerland or Serbia, or a Leipzig team who lost their star defender, Josko Gvardiol, to City during the close season.

Record 14-time winners Real Madrid are always contenders in the Champions League, although Carlo Ancelotti's team find themselves in a difficult group alongside Napoli, Braga and newcomers Union Berlin.

Bayern Munich have reinforced in attack with the signing of Harry Kane, while Paris Saint-Germain have lost Neymar and Lionel Messi but kept Kylian Mbappe and strengthened around him.

Both of their seasons will be defined, as ever, by their performances in the Champions League.

Arsenal will hope to make an impression on their return to the Champions League for the first time since 2016/17, while Saudi ownership has propelled Newcastle United back into the competition after two decades away.

However, they find themselves in a section along with PSG, AC Milan and Borussia Dortmund.

UEFA might have been less inclined to change the format of the Champions League format if their competition featured groups like that more often.

"It's hard and challenging but I think there's some great European games for us to experience and great places to visit for our supporters," said the Newcastle manager Eddie Howe after the draw.

His team begin away to seven-time European champions Milan on Tuesday.