JOIN USAjax Amsterdam and AC Milan, who have twice met in the final of Europe's top club competition and won the title 11 times between them, clash again on Tuesday in a Champions League match which is far from the heady days of their past.
Manchester City's attempt to progress beyond the group stage for the first time continues when they host champions Bayern Munich while Russian pair CSKA Moscow and Zenit St Petersburg will both attempt to collect their first point.
Swiss champions FC Basel, who provided the only shock of the opening matches by winning at Chelsea, could also upset Schalke 04 if they can make the most of the Bundesliga team's leaky defence and Celtic will attempt to repeat last year's upset home win over Barcelona.
Possibly the week's most intriguing game is in highly competitive Group F where Arsenal host Rafael Benitez's Napoli, who began with a 2-1 home win over last season's runners-up Borussia Dortmund and are still unbeaten in all competitions under the Spaniard's leadership.
AC Milan, who won the last of their seven European Cup and Champions League titles in 2007, have been struggling to rebuild since offloading a number of top players one year ago.
They have had a terrible start to this season, picking up only two Serie A wins in six games and scraped past Celtic 2-0 in their opening Champions League match. New signings Riccardo Saponara and Kaka have both suffered injuries.
Milan and Barcelona are expected to progress from the group, although the Catalans will not be looking forward to visiting Celtic where they lost 2-1 last year.
Group D looks straightforward with Manchester City and Bayern Munich, who both won their opening games 3-0 against CSKA Moscow and Viktoria Plzen respectively, clear favourites to progress regardless of the outcome of Wednesday's match.
Big-spending City's first two Champions League appearances ended in group stage elimination but their convincing win in Plzen and the vast European experience of coach Miguel Pellegrini suggest they will do better this time.
CSKA host Plzen in the other game and the Czech champions, making their second appearance, have already learned some painful lessons.
CSKA's compatriots Zenit host group stage debutants Austria Vienna in Group G, where both teams are aiming to get off the mark after opening day defeats, while Porto host Diego Simeone's Atletico Madrid in a battle for the group leadership.
Anything is possible
Anything could happen in Group B where Basel, who eliminated Manchester United two seasons ago, are at home to Schalke, who have conceded 16 goals in seven Bundesliga games and squandered a 3-1 lead in a 3-3 draw at Hoffenheim on Saturday.
Crestfallen Chelsea, meanwhile, travel to Romanian champions Steaua Bucharest, where they lost 1-0 in the Europa League last season and where another defeat could point them towards the exit door.