What to watch out for in the Champions League

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TUESDAY'S MATCHES

Ronaldo reaches for 100
Cristiano Ronaldo's free-kick equaliser in Real Madrid's 2-1 Group F comeback win against Sporting CP took him to 97 goals in UEFA club competition. A hat-trick at Borussia Dortmund would bring up the first century ever achieved; before Ronaldo and Lionel Messi (current tally: 89) started rewriting the record books, the biggest haul was Raúl González's 76. Then again, Ronaldo and Co may need to be careful at the other end, given Dortmund followed up their 6-0 victory at Legia Warszawa with 14 goals in their next three Bundesliga matches. Moreover, BVB are unbeaten in five home games against the Merengues.
Borussia Dortmund v Real Madrid

First for CSKA and Spurs
Having marked their first UEFA Champions League home match at Wembley with a 2-1 loss to Monaco, Tottenham Hotspur have another first on Tuesday with an inaugural trip to Moscow. In fact, it is also the maiden European fixture at Stadion CSKA Moskva – which the home club inaugurated with a 3-0 success against Terek Grozny on 10 September, followed by Saturday's 1-1 draw with Krasnodar. CSKA wiped out a 2-0 deficit to draw at Bayer Leverkusen in their Group E opener.
CSKA Moskva v Tottenham Hotspur

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Porto's English hoodoo
The first UEFA Champions League visitors to Leicester City are Porto, who will hope to exploit the Foxes' inexperience to end a wretched record in England. Sixteen times have Porto visited English clubs in European competition and not once have they won, drawing twice (including, admittedly, a famously celebrated result at Manchester United) and losing 14, most recently 2-0 at Chelsea last term. They are also two points adrift of Group G pacesetters Leicester, who like CSKA are hosting European football at their relatively new stadium for the first time, having previously held UEFA fixtures at the pre-2002 Filbert Street.
Leicester City v Porto

Dinamo and Legia's fresh starts
Matchday one brought defeats for Dinamo Zagreb and Legia Warszawa on top of stumbling domestic form, so both will have different coaches compared with a fortnight ago. Dinamo crashed 3-0 at Lyon in Group H, just days after their unbeaten run spanning more than 100 home league games ended, and their subsequent 5-2 loss at Rijeka led to Zlatko Kranjčar's resignation. Željko Sopić will be caretaker coach as Juventus and old boy Marko Pjaca come to town. Meanwhile in Group F, Sporting CP-bound Legia, thrashed 6-0 by BVB amid a wretched start to the Polish season, have said goodbye to Besnik Hasi and appointed Jacek Magiera.
Dinamo Zagreb v Juventus & Sporting CP v Legia Warszawa

WEDNESDAY'S MATCHES

Celtic bouyed by English record
Overall from 18 matches against English opponents in Europe, Celtic have seven wins and five draws, while in their two group-stage home games involving Premier League clubs they beat Man. United 1-0 in 2006/07 and drew 1-1 two years later. This is Celtic's first competitive meeting with Manchester City though there are plenty of links between the Group C rivals – the Scottish champions not only having Patrick Roberts on loan from the English side but also fiielding their former players Kolo Touré and Dedryck Boyata. Even the son of Celtic chief executive Peter Lawwell works for City as scouting information and content manager.
Celtic v Manchester City

Will Messi be missed?
While some of the focus for Barcelona's trip to Borussia Mönchengladbach will be on Marc-André Ter Stegen's return to his old team, that has been overshadowed by news that Lionel Messi will miss the visit to Germany with a groin injury. Messi, of course, got a hat-trick in the opening 7-0 dismantling of Celtic, yet when the forward sat out six weeks of action with a groin problem this time last year, Barcelona won all three of their UEFA Champions League fixtures – and between them Neymar and Luis Suárez managed 18 goals in nine competitive outings.
Borussia Mönchengladbach v Barcelona

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Xhaka's Basel reunion
It was at Basel that Granit Xhaka burst onto the footballing scene as a teenager between 2010 and 2012, helping knock Man. United out of the UEFA Champions League; now, having joined Arsenal from Mönchengladbach, the midfielder finds himself in opposition to the Swiss champions for the first time. Xhaka is certainly hitting form for Arsenal – witness his fine strikes against Hull City and Nottingham Forest – and like when his Switzerland side played Albania at UEFA EURO 2016, he may even face his brother Taulant in this Group A encounter.
Arsenal v Basel

Simone's unfinished business
This Group D duel a rematch of last term's semi-final between Atlético Madrid and Bayern München, with Diego Simeone no doubt hoping for a repeat of the 1-0 first-leg home win that fired the Spanish team to an away goals victory. Now Carlo Ancelotti is at the Bayern helm, and that also means a sequel to another big match from recent seasons – when the Italian's Real Madrid overcame Simone's Atlético in the 2014 final (though there will be no extra time on Wednesday of course).
Atlético Madrid v Bayern München