AFP Sports looks ahead to Tuesday's Champions League action as Cristiano Ronaldo goes back to first club Sporting Lisbon and Tottenham Hotspur face a crunch trip to Monaco (kick-offs 1945 GMT unless stated):

MONACO V TOTTENHAM HOTSPUR

Tottenham travel to the Mediterranean principality boosted by claiming a first win in eight matches at the weekend, when they beat West Ham United 3-2 after a dramatic late fightback in the Premier League. Mauricio Pochettino's side are in real trouble in the Champions League having lost at home to Monaco and Bayer Leverkusen. They will be eliminated if they fail to win at the Stade Louis II and Leverkusen better their result when they face CSKA Moscow in Russia. Monaco need only draw the game to be sure of a place in the last 16. They will secure first place if they win and Leverkusen drop points. Leonardo Jardim's side are the leading scorers in Europe's big five leagues, averaging three goals a game in Ligue 1, including a 3-0 win at Lorient on Friday. Leading their attack is a revitalised Radamel Falcao, with the Colombian having netted nine times in all competitions this season.

SPORTING LISBON V REAL MADRID

Cristiano Ronaldo takes on his first professional club Sporting as a champion of Europe with Real and Portugal and is widely expected to pick up his fourth Ballon d'Or. He will doubtless receive a hero's welcome on his return to the Estadio Jose Alvalade. Ronaldo's hattrick this weekend, his 39th for Real, delivered a 3-0 away win at Atletico Madrid despite the visitors missing six key players in captain Sergio Ramos, Pepe, Casemiro, Toni Kroos, Alvaro Morata and Karim Benzema. Champions League holders Real won the reverse fixture 2-1 and are unbeaten in 29 games in all competitions. All Zinedine Zidane's men need here is a point to secure passage to the next round, but with Dortmund top of the group by two points Real will want to hunt them down as a point of pride -- and to earn an easier draw in the next round. Sporting are on an upturn and scoring regularly and are still in with a chance of the Europa League.

SEVILLA V JUVENTUS

This is arguably the match of the round with Sevilla top on 10 points and visitors Juve second on eight with a tight 0-0 draw in Italy in the reverse fixture. Sevilla are flying high in Spain after they produced a stunning fightback from 2-0 down to win 3-2 at Deportivo la Coruna. Argentine coach Jorge Sampaoli's version of Sevilla is thrilling fans after transforming the Europa League champions into a free-thinking outfit. Italian champions Juventus go into the showdown on the back of a 3-0 Serie A win over Pescara. "It's an important game for us because we have to win one of our last two games to go through," coach Massimiliano Allegri said. Juve may have to do it the hard way with several defenders carrying knocks, but the forward line of Mario Mandzukic and Gonzalo Higuain is a frightening prospect for Sevilla.