It's the business end of the Champions League, where heroes are made and Ballon d'Or winners forged. But which players will prove most pivotal to their team's success? This week, with Paris St-Germain facing Bayern Munich and Atletico Madrid hosting Arsenal in the semi-finals, we're looking at those key cogs among the clubs battling for Europe‘s grandest prize. This is not a list merely of the biggest stars - although many of them feature - but those players whose presence could be vital to their team reaching the final in Budapest. You can have your say at the bottom of the page too.

10. Matteo Ruggeri (Atletico Madrid)

Matteo Ruggeri has started 11 of Atletico Madrid's 14 games in this season's Champions League and, with Diego Simeone's side up against an Arsenal outfit who beat them 4-0 earlier in the competition, it figures that the left-back will be an important presence in the semi-finals. The La Liga outfit have used a low block more times than anyone else - 458 times in 14 games - and 23-year-old Italian Ruggeri has played a key role in helping Atletico preserve leads. He has made more interceptions than any of his team-mates and is third overall in the competition this season with 20, while no Atletico player has won more tackles than the battle-hardened Ruggeri, who finished the return leg against Barcelona with blood seeping from his forehead.

9. Bukayo Saka (Arsenal)

Ruggeri was tasked with trying to keep Lamine Yamal quiet during the quarter-finals, and his job this time might be trying to stifle Arsenal's Bukayo Saka. The England winger missed more than a month with an Achilles problem, including both legs of the quarter-final win over Sporting, but, given the Gunners struggled to break down the Lisbon outfit in his absence - and taking into account Atletico’s penchant for a low block - Saka may prove key to unlocking their defence. Opta has Arsenal down as marginal favourites to win the Champions League this season, ahead of Bayern Munich, and Mikel Arteta's side have been a different beast with Saka in the line-up, averaging 2.6 goals and 2.3 expected goals (xG) per game in the eight matches the 24-year-old has played compared to only 1.5 goals and 1.8 xG on average in the four he missed.

8. Achraf Hakimi (Paris St-Germain)

Legendary Brazilian right-back Cafu recently claimed Achraf Hakimi is the best in the world in that position, and it's hard to argue given his contributions to Paris St-Germain in the Champions League this campaign. The Parisiens boast a potent threat on both flanks with Nuno Mendes offering similar output from left-back, but we'll go with Hakimi as being more important to their attempt at retaining the European crown given Lucas Hernandez has shared the left-back load with Mendes this term. Bayer Leverkusen's Alejandro Grimaldo is the only defender to edge Moroccan Hakimi for goal contributions in this season's competition, making five assists and scoring once. But Hakimi (7.5 on average per game) and Mendes (7.6) are a long way clear when it comes to defenders who have been involved in the most attacking moves per game.

7. Joshua Kimmich (Bayern Munich)

This could equally have been Aleksandar Pavlovic, who has completed more passes than any of his Bayern Munich team-mates in the Champions League this season and was superb in the win over Real Madrid, but I've gone with Joshua Kimmich for his importance to a side who rightfully tend to get most plaudits for their attack. The 31-year-old midfielder has been key to unleashing that ruthless frontline, with his 19 defensive line-breaking passes the most in Europe's showpiece competition. He is the only Bayern player in double figures. Only irrepressible PSG midfielder Vitinha (345) has made more successful passes into the final third than Kimmich (301) and Pavlovic (285), but Kimmich has got the ball into the penalty box more than any other player this season.

6. Khvicha Kvaratskhelia (Paris St-Germain)

Ousmane Dembele racked up eight goals and six assists in Europe during his Ballon d'Or-winning campaign last season, the record for a PSG player in a season as they clinched the Champions League for the first time. Yet at the semi-final stage this time around Khvicha Kvaratskhelia is only one shy of that, with his eight goals and five assists putting the Parisiens on course to defend their crown. The Georgia winger is as effective as he is mesmerising, taunting opposition with a languid but unstoppable dribbling style, socks at half mast on his calves, defenders clawing at the scorched turf left behind him. He's deadly - and Bayern know it. Khvicha Kvaratskhelia won the Champions League with PSG last season after arriving from Napoli.

5. Michael Olise (Bayern Munich)

From one electrifying winger to another. Michael Olise has been a revelation this season and the only reason he isn't higher on this list is that Vincent Kompany's side have a plethora of forward options ready to chip in on the rare occasion the France international is not firing. Luis Diaz, Serge Gnabry and Lennart Karl have all made significant contributions behind Harry Kane too. But that doesn't take away from just how good Olise has been. The 24-year-old former Crystal Palace and Reading man has completed the third-most dribbles in the competition and is third for big chances created. Barcelona's Lamine Yamal tops both those metrics. Most impressively, Olise has racked up 20 goals and 29 assists in all competitions.

4. David Raya (Arsenal)

David Raya is the representative here for that core Arsenal defensive triumvirate which also includes centre-backs William Saliba and Gabriel Magalhaes. In the 22 Champions League games the three have started together for Arsenal, they have kept 13 clean sheets and conceded 11 goals. That means they are only letting a goal slip once every two games on average, and they boast an impressive record of 59% of matches in which they have not conceded at all. But Raya has stood out for his performances in Europe. He might be renowned for his ability with the ball at his feet, but it was his sublime shot-stopping that kept Arsenal in the quarter-final during the first leg at Sporting. The 30-year-old Spaniard has saved 90% of shots he has faced in this season's competition, putting him well clear of his gloved counterparts. David Raya made five saves in Arsenal's quarter-final first-leg win at Sporting.

3. Julian Alvarez (Atletico Madrid)

Atletico Madrid's trip to Arsenal in the league phase feels a long time ago, but it will stick in their mind not just for the four goals they shipped, but for their struggles in attack. Atletico produced only 0.32 xG from open play in that defeat and managed only one shot on target, so, if they are to take anything against Arsenal this time around, getting Julian Alvarez in the game will be key. The Argentina forward has scored nine goals in the competition this season, more than any Atletico player had managed in a Champions League campaign. He's also a menace defending from the front, with a mammoth 853 high-intensity pressures - more than anyone else this season. That's 70 per game on average. That work ethic, ruthlessness in front of goal and the wizardry to bend a free-kick into the top corner, as Barcelona found out, make the 26-year-old vital to Atletico's chances of progressing.

2. Vitinha (Paris St-Germain)

Vitinha has already been mentioned several times in this column because he happens to be the yardstick for the best midfielders on the continent. The diminutive Portugal international, once of Wolves, makes Luis Enrique's European champions tick. His passing stats put Vitinha in the conversation with Barcelona and Spain great Xavi. He is streets ahead in terms passes completed in the Champions League this season, never mind passes into the final third and forward passes. In fact, his 1,370 passes this term are the most in any edition of the competition since Opta started tracking such stats in 2003-04. Vitinha has completed 100 or more in eight different games this season, which has been topped by only one player - Xavi in a peak Pep Guardiola Barcelona team of 2010-11.

1. Harry Kane (Bayern Munich)

In top spot it has to be Harry Kane. Goals win games, and the England captain has scored 53 of them in 45 games in all competitions for Bayern Munich this season. The most prolific forward on the continent right now has netted in his past four Champions League knockout games. His 12 goals are the most by an English player in a season of Europe's top competition. A first European trophy is on the line but also potentially the prize of being named the world's best player. It's a Ballon d'Or-worthy season from the 32-year-old, but Kane will know that individual accolade often only comes with team success. Kane's presence is crucial to Bayern and he is the star who could have the biggest say on which cabinet the Champions League trophy ends up in.

Harry Kane has scored a record 78 goals in 112 games for England.