Arsenal went five points clear at the top of the Premier League with a battling display against the 10 men of Chelsea.
The Gunners were not at their best against a much-improved Chelsea but still left with a point that strengthens their position at the top of the table.
In a fiery first half, Arsenal had four men booked and Blues midfielder Moises Caicedo was shown a straight red card for a high challenge on Mikel Merino which was upgraded from an original yellow.
Chelsea reacted well to going a man down and frustrated Arsenal while carrying a threat of their own.
The 10 men then took the lead with a goal out of the Arsenal handbook as Trevoh Chalobah flicked on Reece James’ excellent near-post corner and the ball drifted in at the far post.
But the leaders fought back and after Bukayo Saka turned Marc Cucurella inside out and crossed, stand-in forward Merino buried a header.
Merino has now scored 10 Premier League goals, seven of which have been headed.
Arsenal had Martin Odegaard, Gabriel Jesus and Viktor Gyokeres all back on the bench after injury and introduced their captain and striker Gyokeres, but they were restricted to just eight shots, with Chelsea having 11.
Chelsea left Cole Palmer on the bench throughout despite Enzo Maresca calling him his best player in the build-up.
There was a late flashpoint whhen Gyokeres slid in late on goalkeeper Robert Sanchez but a yellow card sufficed for the former Coventry man.
Chelsea move third, level on points with Aston Villa and six off the pace set by Arsenal.
