Alexis Sanchez’s sublime lob and Mesut Ozil’s hat-trick spearheaded Arsenal’s 6-0 Champions League thrashing of Ludogorets at the Emirates Stadium.

Sanchez’s first goal in four games sparked Arsenal’s second win in three European games, stretching the Gunners’ unbeaten run to 11 matches in all competitions.

Theo Walcott and Alex Oxlade-Chamberlain also hit the net, with Ozil’s second-half hat-trick helping Arsenal retain top spot in Group A.

The Gunners remained above Paris St Germain on goal difference, after the French side beat Basle 3-0.

Lionel Messi hit a hat-trick as Barcelona thrashed Manchester City 4-0 at the Nou Camp to seal a nightmare return for former boss Pep Guardiola.

Guardiola watched his side crumble in their Champions League Group C clash after the 53rd-minute sending-off of another former Barcelona star, keeper Claudio Bravo, for handling outside his box.

Messi had opened the scoring in the 17th minute and went on to complete his hat-trick just past the hour-mark before Neymar – who earlier missed a penalty – added a late fourth.

Celtic’s Champions League aspirations were blown apart by Borussia Monchengladbach who were more than worth their 2-0 win at Parkhead.

The Hoops went into the game buoyed by their 3-3 draw with Manchester City on match day two last month.

However, keeper Craig Gordon had to make several crucial saves in a first half largely controlled by the slick-moving Bundesliga outfit who picked up their first points in Group C.

Yannick Carrasco scored the only goal of the game as Atletico Madrid maintained their 100 per cent record in Champions League Group D with a 1-0 win at Rostov.

The visitors went into the game on the back of a four-game winning streak culminating in a 7-1 thrashing of Primera Division rivals Granada on Saturday.

And although they were not able to repeat such a rout against a resolute Rostov defence, Carrasco’s 62nd-minute volley from a Juanfran cross proved enough to give Atletico the points.

Vincent Aboubakar’s header four minutes from time earned Besiktas victory at Napoli as the Turkish side edged a Champions League thriller 3-2.

The home side twice pegged back their visitors and thought they had gone ahead late on, only to see Manolo Gabbiadini’s strike ruled out for offside.

And Aboubakar then nodded in his second goal of the game from Ricardo Quaresma’s free-kick late on, ensuring Napoli dropped points for the first time in this year’s competition as Group B was blown wide open.

Bayern Munich won for the first time in four games as Joshua Kimmich’s scoring run continued in a 4-1 success over PSV Eindhoven.

Carlo Ancelotti’s side had not recorded a victory since defeating Hamburg 1-0 at the end of September but they were far too strong for their Dutch opponents in this Champions League tie.