It's back. Europe's premier club competition has started again after four months away from our screens. And it was back with a bang, too. None of Tuesday's games had fewer than two goals and one even had seven in the case of Real Madrid's hammering of Galatasaray in Turkey.

There are 32 teams going for glory in the Champions League, with half of the first set of matches now complete. Of course, realistically only a handful have any chance of winning it, but this stage of the competition always has a certain level of intrigue. Here, Sports Mole considers some of the key performers from the first night of action.

Cristiano Ronaldo:

World record summer signing Gareth Bale was left on the bench for Real's trip to Galatasaray, which left the previous record holder Cristiano Ronaldo to work his magic in Turkey. Ronaldo is used to being the main man in Madrid and, despite the arrival of the Welshman, with performances like the one he put in is still absolutely key to this Real side.

In the first half the Portuguese was quiet on the whole, which is always surprising to see from a player of his calibre. A great deal of credit should go to Emmanuel Eboue who dealt with him well, but keeping Ronaldo quiet for 90 minutes and not just 45 is a different prospect entirely. In the second half Ronaldo netted his 21st hat-trick since moving to the club from Manchester United.

Ronaldo's - and indeed Real Madrid's - performance was typical in the second half. His first goal was a classic counter-attack, as he tapped in from Angel di Maria's cross, before he rose high to head in a Bale free kick. He then produced a fine assist for Karim Benzema before completing the rout himself late on. A Ronaldo on this form could see Real go a long way in the tournament.

Wayne Rooney:

Recently Wayne Rooney has not been a key member of the Manchester United squad, but against Bayer Leverkusen he put in a performance of the highest quality. German opposition in Europe are always tough foes and it was Rooney who was the difference-maker on Tuesday night. His performance was what gave United the edge in the six-goal thriller at Old Trafford.

Rooney was involved in three of United's four goals and was key to the win, and even managed to miss a sitter on the night. He opened the scoring, although Antonio Valencia did appear to be obstructing Bernd Leno from his volley. There was no luck about his second, however, as he finished off an unlikely move that started with a long ball from David de Gea.

It was not only his goals, however. Rooney's movement was fantastic as he dropped deep and timed his runs forward perfectly. This was summed up by his assist for Valencia's fourth. He was the outlet for the break and swept the ball into the path of the winger who finished well. On this showing, Rooney certainly suggested that he can be important for United. After all, his 199th and 200th goals put him in the distinguished company of Sir Bobby Charlton, Denis Law and Jack Rowley in the 200 club.

David Alaba:

There are many players in the Champions League-winning Bayern Munich side who have the ability to change games. One of the more surprising ones, perhaps, is Austrian left-back David Alaba. However, in the 3-0 win against CSKA Moscow he was quite magnificent. His performance highlighted the fluid football that Pep Guardiola wants his side to play, as Alaba was on the left, right and up front at times.

Alaba's movement was evident from even the third minute, as he was fouled in the attacking midfield position to win a free kick. Not only did he win it, but he stepped up to send a dipping effort into the bottom corner to give Bayern the perfect start.

His performance remained at the same level for the rest of the game, frequently finding himself having swapped with one of the midfielders to try to make the final pass. His forward running culminated in a deserved assist, as he clipped over the CSKA defence to Arjen Robben, who chested down and fired home for 3-0. If Alaba's performance is anything to go by, Pep's Bayern will be too strong for most teams in this year's tournament.