Robert Rowan used to spend his working week scouring the continent as a former opposition scout for the Scottish Football Association. His little black book is a veritable who's who of European football. Ronaldo, Messi, Toure and Costa - all the usual names are contained inside it but he also knows his Hakan Calhanoglus from his Youri Tielemans. Here he runs the rule over those players he knows will light up this year's Champions League group stages which return tonight - and those who he thinks we'll be hearing much more of . . .

GROUP A

Star of the group Koke (Atletico Madrid) Played an important part in Atletico's success last season and was also a European Under-21 Championship winner with Spain last year. He is 22 now and I reckon he will be on the move next summer with Barcelona and Real Madrid watching closely.

One to watch Kingsley Coman (Juventus) Rated very highly in French Football and was wanted by almost all of the big clubs this summer Arsenal, Liverpool and Manchester City to name a few but the lure of the "old lady" and playing with compatriot Paul Pogba allowed Juventus to sign him this summer from the clutches of Paris St-Germain. At the age of 18, it was surprising to see he was announced in the Champions League squad and I doubt he will feature regularly but if he does he will impress.

GROUP B

Star of the group Cristiano Ronaldo (Real Madrid) There's not much that can be said that hasn't been said already. However, the Portuguese forward struggled with his fitness at the World Cup finals to the extent that doctors warned him he could risk finishing his career if he played through a chronic knee problem. The 29-year-old is unlikely to be dimmed by opponents - he scored 17 times in this competition last season - but his commitment to his club has come under increasing scrutiny and he was publicly critical of Florentino Perez's transfer policy during the summer leading to further speculation that this season might be his last at the Santiago Bernabeu. It's rarely dull where Cristiano's concerned.

One to watch Raphael Varane (Real Madrid) He is one of the best centre backs in the competition but that still doesn't guarantee him a place ahead of two liabilities in Sergio Ramos and Pepe. Carlo Ancelotti is a coach who appears unwilling to disturb the changing room, with Ramos and Pepe two massive characters with as much if not more influence than the Italian coach. However, due to Real's poor start don't be surprised to see Ancelotti call on Varane as he can now use defeats as an excuse to make changes.

GROUP C

Star of the group Salomon Rondon (Zenit St Petersburg) Rondon will lead the line for Andre Villas-Boas's Zenit side. He is a very powerful striker who is at his most effective in the air. That serves as an ideal foil for the three attacking midfielders playing behind him (Hulk, Oleg Shatov and Danny). He is an excellent finisher and will provide a threat to any defence.

One to watch Hakan Calhanoglu (Bayern Leverkusen) Exciting playmaker who is full of tricks and creativity. A set-piece specialist, the Turkish international midfielder is capable of scoring spectacular goals and will be look to add to his tally during this campaign. Hakan is very important to the way Roger Schmidt sets his team - a high press, attacking football with an objective of scoring as many goal as possible rather than focusing on defensive structures.

GROUP D

Star of the group Mats Hummels (Borussia Dortmund) A Rolls Royce of a centre back, who can organise the back line, is excellent in one v one defending situations and has great strength and power. Hummels was appointed captain this summer in order to retain his services as Manchester United, Barcelona, Paris St-Germain hovered.

One to watch Youri Tielemans (Anderlecht) Only 17, but hr plays an important part in the team by structuring attacks from midfield. Tielemans will be the next Belgian talent who will get his move to greater things. I have no doubt about that having seen him play when I was working for Scotland and followed his progress since. It's a difficult group for Anderlecht but keep an eye on this boy.

GROUP E

Star of the group Yaya Toure (Manchester City) The Ivorian is one of the best in the world and in his role one of the best of all time. The way he creates the transition from defence to attack is exceptional - he is strong, powerful, technical, intelligent and he scores goals. Against Bayern, I wouldn't be surprised to see Man city play a middle three of Fernando, Fernandinho and Yaya Toure which will be near enough impossible to get through.

One to watch Juan Iturbe (Roma) A very talented winger who was signed in the summer from Verona for €22m. He's excellent in the final third, very successful in one-v-ones and can deliver a great ball into the box. Faces great competition at International Level to get a place(Argentina) but he will be looking to prove a point this season.

GROUP F

Star of the group Lionel Messi (Barcelona) In my mind the best player of all time. However, he showed signs of diminishing powers last season, not least because of injuries. He has started this season in the same manner and it would be a travesty if Barca were denied his services for any significant period of time.

One to watch Lucas Digne (Paris St-Germain) When a manager asks you to find a left back it's always the hardest position to fill. Digne would have been at the top of the list for the heavyweight clubs list this summer. I am almost certain that in the next three years he will have become one of the best left backs in the world. Technically very skilful, athletic, Digne understands his responsibilities and constantly provides an attacking option.

GROUP G

Star of the group Diego Costa (Chelsea) I had no doubt Costa would be a success at Chelsea, his profile suits one of those who you would ask to lead the attacking line. He is physical, likes to bully the opposition, technically very good with his back to goal or facing goal and a very good finisher.

One to watch Julian Draxler (Schalke) Likely to get his move to a bigger club this year and was very close to a move to arsenal during the last transfer window. Didn't feature as much as he would have wanted for the German National Team at the World Cup but he will be a key player at the next World Cup that's for sure. Very direct winger/inside forward who has great creativity and also shooting ability from long distance.

GROUP H

Star of the group Iker Munian (Athletic Bilbao) Just 21 but has six years of experience in the first team having arrived on the scene at 15. A skilful, attacking player, Munian is agile, mobile and dynamic. He's very difficult to stop in a one-v-one and is most effective when cutting inside.

One to watch Ruben Neves (Porto) Not long turned 17 and is hotly tipped to play an important part in Porto and Portugal's future. He's very composed in possession and has a varied range of passing with excellent accuracy. Rated as one of the best players at the recent Under-17 European Championships and scored on his debut for Porto.