The meeting between the two clubs, who have won 16 European Cups between them, is the pick of matchday three in the continent's elite club competition. Chelsea travel to Moscow to play Spartak on Tuesday knowing that a third victory in three games would virtually assure them of a place in the last 16, while Arsenal are also looking to continue their perfect start when they host Shakhtar Donetsk.
Wednesday features holders Inter Milan hosting Tottenham Hotspur, Barcelona playing FC Copenhagen and Manchester United taking on Bursaspor.
Portuguese international Ronaldo has taken longer than usual to get into his stride this season and Real fans whistled at him for several lacklustre performances at the Bernabeu.
However, after scoring twice against La Liga rivals Deportivo Coruna on October 3, he netted another double and set up two for striker Gonzalo Higuain in Real's 4-1 victory at Malaga on Saturday and is eagerly awaiting Milan's visit.
“I knew that things would come together and thank goodness they are coming together. I am very happy and full of confidence,” Ronaldo told reporters. “We know that if we win (against Milan on Tuesday) we are a step away from qualifying for the last 16. We are playing at home and have an obligation to win.”
Real, coached by Ronaldo's compatriot Jose Mourinho, began their bid for a 10th European Cup with victories over Group G rivals Ajax Amsterdam and Auxerre and top the standings on six points. Milan were held to a 1-1 draw in Amsterdam at the end of last month and are second on four.
Despite their recent brilliant form, Spain goalkeeper Iker Casillas warned that a showdown with the Italian giants was a completely different matter. “Madrid v Milan is a classic European encounter. All rivals are tough but this is perhaps our first big test of the year,” Real's captain told reporters.
Milan injury doubts over centre back Thiago Silva, courted by Real in the close season, after the Brazilian suffered an ankle injury on Saturday. Goalkeeper Christian Abbiati also suffered a knock in the game but is expected to be fit while captain Massimo Ambrosini is still out.
Chelsea return to the site of their most painful Champions League defeat when they take on Spartak at the Luzhniki stadium in the top-of-the-table Group F clash. It will be Chelsea's first visit to the 80,000-seat arena since their heartbreaking loss in the 2008 final against Manchester United in a penalty shoot-out when captain John Terry slipped on wet grass and missed the decisive spot kick.
The London club and their Russian billionaire owner Roman Abramovich will hope to avoid another slip-up this time, with the match being played on an artificial turf. For Spartak, holders of the unenviable record of 22 successive Champions League games without a win that stretched for more than five years between 2001 and 2006, Tuesday's match will be the stiffest test yet of their European ambitions.
The Russians, who like Chelsea have a 100 percent record in the group after beating French champions Olympique Marseille and Slovakia's Zilina in their first two games, are well aware that another win would almost certainly secure them a place in the knockout round for the first time since the 1995-96 season.
“We had a great start, probably better than some of our fans had expected,” Spartak coach Valery Karpin told local media. “But we all know that beating Chelsea would be a totally different proposition from what we had before. So we're not getting carried away by any means.”
