UEFA.com rounds up key stats from the round of 16 first legs, including two landmarks for Real Madrid CF and Lionel Messi equalling Raúl González's one-club tally.
• Real Madrid CF became not only the first club to score six goals away from home in a UEFA Champions League knockout fixture but also the first to reach 400 goals for the competition, Cristiano Ronaldo's second goal of the evening at FC Schalke 04 (and Madrid's sixth) bringing up that landmark figure.
• FC Barcelona's victory over Manchester City FC and Manchester United FC's defeat at Olympiacos FC combined to move the Catalan side ahead of United to the top of the table in the UEFA Champions League's official all-time ranking list. While both clubs have a nominal 263 points (on the basis of two points for a win, one for a draw), Barça have the superior goal difference (+186 to +155). They have also played fewer games (190 to 197).
• Barcelona also have more wins now than United, 107 to 106, but both teams still trail Real Madrid in that category, the latter's victory at Schalke being their 111th in all. Madrid are the only club in the competition's history (with a minimum of ten matches played) to average over two goals a game, the 6-1 triumph in Gelsenkirchen boosting their average to 2.041. Next best are Barcelona on 1.984.
• Three players made their 50th UEFA Champions League appearance on matchday seven – Yaya Touré of Manchester City, FC Zenit's Anatoliy Tymoshchuk and Nemanja Vidić of Manchester United. Meanwhile, Chelsea FC goalkeeper Petr Čech took his all-time total to 99.
• Lionel Messi's penalty at Manchester City was his 66th goal in the competition for Barcelona, matching the record number scored for one club, by Real Madrid's Raúl González. Messi needs another five goals to equal Raúl's competition-best haul of 71 – the Spaniard also struck five times in the competition for Schalke.
• Ronaldo's double for Madrid took his cumulative tally of UEFA Champions League goals to 61, five behind Messi, although he is still only the third player to reach 60 goals in the competition. However, with 11 in this season's tournament he is on target to eclipse the Barcelona forward's record for a single campaign – 14 in 2011/12, on a par with the European Cup mark set by AC Milan's José Altafini in 1962/63.
• Both Messi and Ronaldo have found the net in every one of their UEFA Champions League outings this term – a feat matched by Club Atlético de Madrid's Diego Costa, whose late winner at AC Milan was his fourth goal in as many appearances.
• With his late strike at Arsenal FC, FC Bayern München's Thomas Müller became the 35th player to attain the milestone of 20 UEFA Champions League goals. Fernando Torres and Robert Lewandowski both took their all-time totals to 17, with the former notching his ninth for Chelsea FC – one more than he managed for Liverpool FC.
• 2013/14 is only the second season in which two countries have taken their full four-team complement into the round of 16. England and Germany are at full strength this term; it was England and Spain who between them accounted for half the field at this juncture in 2008/09.