UEFA Champions League: 5 Games To Watch on Matchday 2

The Champions League group stages are back in session this week, with Matchday 2 offering up some intriguing battles across Europe.

While there should be relatively easy nights ahead for last year's champions Barcelona and runners-up Manchester United, several of their closest rivals face tough tests.

Here are my five games to watch this week.

Bayern Munich vs. Manchester City

City were held to a 1-1 draw by fellow Champions League newcomers Napoli in their opening game, while Bayern had an impressive 2-0 win away at Villarreal.

Tonight they meet in Munich, with both knowing a defeat could have big implications for the outcome of their group. Free-scoring City harbor ambitions of victory, but Bayern are a tight defensive unit unlikely to be easily ruffled.

CSKA Moscow vs. Inter Milan

Inter fell to a shock 1-0 defeat to Trabzonspor at the San Siro on Matchday 1, a result that played a big part in the sacking of Gian Piero Gasperini.

New coach Claudio Ranieri got off to a winning start in Serie A, and his first task in the Champions League is a difficult trip to face CSKA Moscow. Inter surely need a draw at the very least to get back on track.

Valencia vs. Chelsea

Just a month after leaving the club, Juan Mata returns to face former club Valencia in the colours of Chelsea.

Andre Villas-Boas's team got off the mark with a home win against Bayer Leverkusen, but should face a difficult test in Spain. Valencia have got off to a decent start to the La Liga season and held Barcelona to a 2-2 draw at home last week.

That said, they lost their group stages opener to Genk.

Napoli vs. Villarreal

Back to Group A for the clash between Napoli and Villarreal.

The Spanish visitors have had a pretty uninspired start to the season and will be desperate to take something away from Italy.

Meanwhile Napoli will be thinking this a must-win game in arguably the toughest group of the lot. But which Napoli will turn up? The side who beat Milan 3-1? Or the one that lost 1-0 at Chievo?

Real Madrid vs. Ajax

My final selection is the meeting of two European giants who have fallen short in recent years.

The last of Ajax's four titles came in 1995, since when the Dutch masters have failed to mount a serious challenge.

Nine-time winners Madrid last won the Champions League in 2002, and in reaching the semi-finals last season ended a run of six straight defeats in the second round.

Jose Mourinho's team have started the new season well and some have them as favorites to go all the way this time.