A new era in European club football begins this week when the first games are played in the expanded Champions League amid curiosity about the rejigged format as well as growing concerns over an ever-increasing number of matches.

UEFA, the European game's governing body, sensed the need for change at a time when the traditional group stage was becoming more predictable and the continent's biggest clubs were threatening to break away and form their own Super League.

The result is a league phase featuring 36 clubs -- four more teams than in the past -- with everyone playing eight matches against eight different opponents, two more games than previously.

The action starts in earnest on Tuesday, when reigning champions Real Madrid begin their quest for a record-extending 16th title with a home game against VfB Stuttgart, the surprise runners-up in last season's German Bundesliga.

That will be the first ever meeting of the sides, while the same night AC Milan host Liverpool in a heavyweight clash between clubs with 13 European Cups between them.

On Wednesday, Manchester City play Inter Milan in a repeat of the 2023 final won by Pep Guardiola's team.

For one week only, Champions League matches will also be played on Thursday and the line-up will include a glamour tie between Monaco and Barcelona.

The expanded competition also has room for a meeting of two historic names when former champions Red Star Belgrade and Benfica face off in Serbia.

In addition to that, there will be an encounter between French newcomers Brest and Austrian champions Sturm Graz, hardly the kind of tie normally associated with the European elite.

"In the end I think we came to a solution that will benefit all," UEFA president Aleksander Ceferin told Britain's Sky News recently when asked about the new format.

"It will make a more unpredictable and more interesting competition. It is a great change."

The top eight teams at the end of the league phase -- which now runs into January -- will advance to the last 16.

The teams placed from ninth to 24th in the standings will enter a play-off round to contest the remaining last-16 berths, while the bottom 12 teams will be eliminated.

There are greater financial rewards too, with the winners of the competition pocketing over 86 million euros ($95.3m) just in prize money, not including bonuses of 700,000 euros for every point gained in the league phase or income from television.

The draw has thrown up plenty of glamour ties throughout the coming months, including Paris Saint-Germain meeting Arsenal and Manchester City, and Madrid playing Borussia Dortmund, Liverpool and Milan.

It may well prove a success, a breath of fresh air that the competition needed in its early stages, especially as final positions in the league phase will determine seedings in the draw for the knockout rounds.

But there are concerns about the impact on players of the extra matches, especially in a season which will finish for top clubs with the first edition of the expanded FIFA Club World Cup in the United States.

"Sometimes something new can be good for the competition and for everyone, but what we struggle to understand is the increase in the number of matches," admitted Madrid coach Carlo Ancelotti, mindful of the potential added injury risk to his players.

Global footballers' union FIFPro said earlier this month that the sport's governing bodies were "failing to meet their duty of care" towards players by denying them sufficient rest and imposing extra games.

FIFPro said too many players were already playing too many games, but the possibilities for time off appear to only be decreasing.

"We need safeguards for players to limit their travel, ensure rest periods, and provide adequate recovery so they can reach peak performance," said Stephane Burchkalter, FIFPro's acting General Secretary.

For now, the demands are only getting greater, and in the case of the Champions League it remains to be seen if bigger means better.