The Champions League returns on Tuesday and Wednesday with Cristiano Ronaldo and Lionel Messi competing for yet another prize as the rival stars take aim at the tournament’s all-time scoring record.

While the world’s top two players continue their individual battle, three of England’s four teams seek their first win, and the Spanish and Italian champions clash this week in Europe’s top-tier competition. Here are the things to know about this week’s Champions League group games:

Raul’s record: Ronaldo and Messi are neck-and-neck in a race to become the Champions League’s all-time leading scorer by breaking the record held by Raul Gonzalez. Ronaldo has 68 goals in Europe’s top club competition, one more than Messi.

Raul scored 71. Ronaldo may have a better chance of getting there first as Real Madrid plays at Bulgaria’s Ludogorets in Group B on Wednesday, a day after Messi’s Barcelona has a tougher trip to Paris Saint-Germain in (PSG) Group F. The Portugal forward looks primed to increase his goal haul in Sofia after scoring 10 goals in his last six matches, including one four-goal performance and a hat trick. Their latest two-man contest comes after they have divvied up the Ballon d’Or for the world’s best player for the past six years and have taken turns leading the Champions League in scoring for the past seven seasons.