The second lot of Champions League Matchday 2 for 2016/17 fixtures were completed on Wednesday night.
Theo Walcott scored a fist-half brace, taking his recent tally to four in three games, as the Gunners turned on the style at the Emirates Stadium before a more subdued second half.
The French champions fell behind when Nathanael scored for Ludogorets in the 16th minute but rallied through Blaise Matuidi before the break, prior to Edinson Cavani's second-half double saw Unai Emery's men draw equal on points with the Gunners.
The Uruguayan now has eight goals in his past five outings in all competitions, including three in the group stage of the UCL.
Group B saw Besiktas held to 1-1 draw by Dynamo Kyiv despite Ricardo Quaresma opening the scoring with a stunning 25-yard free-kick. Viktor Tsyhankov responded for the Ukrainians in the 65th minute as Besiktas tallied their second point of the group stage, and Kyiv their first.
Marek Hamsik opened the scoring on 20 minutes before a brace from Dries Mertens, either side of a Arek Milik penalty, had Maurizio Sarri's Napoli in cruise control but Goncalo Guedes and Eduardo Salvio ruined what could have been a perfect night for the home team.
Group C threw up a couple of dramatic matches which saw Barcelon come from behind to beat Borussia Monchengladbach 2-1 in Germany.
Thorgan Hazard scored his first Champions League goal to give Borussia a 34th-minute lead before Luis Enrique's Lionel Messi-less Barca kicked into gear with second-half goals from Arda Turan and Gerard Pique.
Moussa Dembele gave the Bhoys an early lead with his first Champions League goal before Fernandinho struck back in the 11th minute. An unfortunate deflection from Raheem Sterling saw Celtic back in front but the winger atoned for his error by levelling on 26 minutes.
Dembele grabbed his second of the night early in the second half before Nolito again equalised for City in the 55th minute, eventually settling for a point after winning 10 in a row under Guardiola.
Bayern pressed for an equaliser but were unable to find the back of the net as Atleti spurned a great chance to kill off the contest late only for Antoine Griezmann to hit the crossbar from the penalty spot.
A double from Dmitry Poloz, either side of Davy Propper's 14th-minute leveller, had Rostov ahead by the 37th minute and despite dominating the contest, conceded a second goal when Luuk De Jong headed home on the stroke of half-time for PSV's 100th goal in their 100th UCL appearance.
PSV were awarded a penalty in the 57th minute when De Jong was brought down but a missed penalty from Propper cost Phillip Cocu's side all three points, having missed from 12 yards in their narrow defeat to Atleti a fortnight ago.
2016/17 UEFA Champions League - group stage scores