Here are 5 things to look out for in Tuesday's Champions League action 💫.

It's time for matchday four of the redesigned Champions League, which boasts some fascinating matchups across the continent.

We examine Tuesday's major talking points.

⚔️ Match of the day

There is a lot of competition for this category, but the match between Liverpool and Bayer Leverkusen at Anfield takes the crown.

It pairs the Premier League leaders against Germany's defending double winners, who are guided by an old Reds favourite, Xabi Alonso.

Liverpool is one of just two teams (the other being Aston Villa) with a perfect record into matchday four, but they face Leverkusen, who have conceded only once in the competition this season.

The game will be thrilling to watch as two of the continent's most exciting and entertaining teams compete.

Leverkusen remains unbeaten in Europe this season, having won two and drawn one of their UCL games. They'll have to work hard to keep this record against Premier League leaders Liverpool, who have won three straight games and conceded only one goal in the league.

🔎 Team to watch.

Holders Real Madrid aren't firing on all cylinders as they prepare for their intriguing showdown with Milan - a game that is a true throwback to the competition's rich heritage in a year that has seen many changes.

Their most recent game was 10 days ago, when they were humiliated at home by Barcelona in El Clásico, and their scheduled weekend match against Valencia was postponed due to catastrophic floods in Spain.

They've also been criticism for their Ballon d'Or boycott, and local media has panned celebrity combo Kylian Mbappé and Jude Bellingham's performances this season.

Madrid leads Milan in head-to-head statistics, having won two of their last five meetings. Milan has one win, and the other two matches have resulted in draws.  

Can Los Blancos quell the growing uproar?

🔥 Player to watch.

Leipzig are desperate for a win on their trip to Glasgow to play Celtic, having lost all of their previous games (although on a difficult run: Atlético de Madrid, Juventus, and Liverpool).

They will rely on main man Benjamin Seško to give spark in Scotland against a Bhoys squad that impressed defensively in their 0-0 draw at Atalanta last time.

The Slovenian has scored all three of his team's Champions League goals this season, requiring only ten shots, while his teammates combined for 34 fruitless attempts.

Potential upset.

Sporting CP is unlikely to interrupt Manchester City's record unbeaten streak in this competition.

However, City fell to Tottenham in the EFL Cup last midweek and then to Bournemouth in the league on Saturday, losing back-to-back games for the first time in over a year, implying a sense of vulnerability at the present.

Sporting is also unbeaten in their past three matches with English teams and has yet to lose in the Champions League this season.

Of course, there's the Rúben Amorim factor. There would be no better way for the incoming Manchester United manager to leave Lisbon than with a victory over the team that will soon become his new foe.

📊 A fascinating statistic

Bologna has never lost any of their 28 home games in major European play (winning 16 and drawing 12).

In fact, Ipswich Town is the only team in Europe to have played more home games without losing, with 30.Can the Italians beat that record when they host Monaco on Tuesday?