David Luiz was sent off in the closing stages as Arsenal held Chelsea to a 0-0 Premier League draw at Stamford Bridge.
Both sides were left to rue missed first-half opportunities in a match between two London rivals that failed to catch fire until the Brazil defender received his first-ever Premier League red card with three minutes remaining.
The Gunners had the better of the opening half and should have gone into the break ahead when Aaron Ramsey hit the post and Alexandre Lacazette somehow fired over from the close-range rebound.
Chelsea had earlier missed a one-on-one opportunity from Pedro, who was foiled by Petr Cech.
The second half lacked the excitement of the first and the introductions of Eden Hazard and Alexis Sanchez from the two substitutes' benches did not provide the desired spark.
And David Luiz saw red for a high challenge on Sead Kolasinac as the game neared its conclusion, marking the third straight match Chelsea have had a player sent off against Arsenal and rounding off a poor performance from Antonio Conte's men.