Cristiano snuck in between two Gunners defenders at the far post to halve the deficit on 34 minutes, after Nemanja Matic's incisive cross.
Our no.7 has become just the 33rd different player to record a century of top-flight strikes since the league was rebranded in 1992.
4 - Since the 2003-04 season, @Cristiano is one of four players to score 100+ goals in two of Europe's big-five leagues (LaLiga, Premier League), along with Edinson Cavani (Ligue 1, Serie A), Gonzalo Higuaín (LaLiga, Serie A) and Zlatan Ibrahimovic (Ligue 1, Serie A).