As the month of May begins, that also means the UEFA Champions League semifinal round begins across Europe.

The first semifinal matchup features a rematch of the 2013-14 and 2015-16 finals as Real Madrid entertain local rivals, Atletico Madrid. Zinedine Zidane’s side are the current holders in this competition, and would like nothing more to eliminate their rivals to make the final in Cardiff.

The second matchup sees the current leaders of the Italian Serie A and the French Ligue 1 divisions square off. Monaco welcomes Juventus to the Stade Louis II on Wednesday, looking to continue their dream run this season. Juventus is looking for their first finals appearance since 2014-15.

Here’s a closer look at this week’s Champions League action:

REAL MADRID VS. ATLETICO MADRID  (TUESDAY, 2:45 P.M. FOX SPORTS 1) 

Injuries of Note: Gareth Bale will miss out for the hosts, dealing with a calf problem, while Atletico right-back Juanfran is out with a thigh issue.

Key to the Game: It will be a clash of two sides with different strengths, and we will see which side can get an opening leg victory. Real Madrid has the likes of Cristiano Ronaldo in attack, which is always dangerous for any opponent. Atletico’s defense has been their strength this season, so look for centerbacks Diego Godin and Stefan Savic to be physical with the Portuguese forward.

Players to Watch: Two of the world’s top forwards will be on display as Cristiano Ronaldo and Antoine Griezmann duke it out. Griezmann has 25 goals across all competitions this season, while Ronaldo has 28. Yhe forward who has the better performances across these two legs could push their side in the final.

Quote: “Atletico always gives us a hard game,” said Real Madrid manager Zinedine Zidane. “The strength they have is that they never give up, no matter what happens. They fight, battle, they know their strengths and use them as best they can.”

A.S. MONACO VS. JUVENTUS (WEDNESDAY, 2:45 p.m. FOX SPORTS 1) 

Injuries of Note: Juventus will be without young centerback Danielle Rugani, who is out for the remainder of the season with a knee problem. Monaco has no injury concerns following their league victory over Toulouse this past weekend.

Key to the Game: Just like Tuesday’s semifinal, Wednesday’s see two sides that excel at different sides of the field. Juventus’ back-line is strong and experienced, and will try to slow down Monaco’s free-flying attack. The hosts have had trouble at times on the defensive side, but will need to be at their best against a Juventus side who have several scoring options.

Player to Watch: Monaco forward Kylian Mbappe is continuing to make a name for himself across all competitions. The 18-year-old striker has 19 goals combined between UCL and Ligue 1 play, helping Monaco to tops in the domestic league as well as a semifinal berth.

Quote: “The game against Atalanta was useful for Wednesday night in that Monaco operate in a similar way: both teams have very good young players who look to play quickly and put you under a lot of pressure,” said Juventus winger Juan Cuadrado. “We need to show our usual solidity, focus and desire all over the field because it will be a very difficult match.”