Arsenal and Chelsea are still level at 0-0 in an eventful and controversial Premier League clash at the Emirates Stadium.
The first effort of the game fell to the hosts as a Santi Cazorla free kick four minutes in flew kindly into the arms of Thibaut Courtois.
Chelsea appealed for a penalty in the seventh minute when Oscar went down in the box under a challenge from Hector Bellerin, but referee Michael Oliver turned the calls down.
Drama continued to flow at the Emirates as Branislav Ivanovic was lectured for scything down Alexis Sanchez and Courtois sliced a miscued back-pass out of play as Sanchez bore down on him.
There was another penalty shout from Jose Mourinho's side just after the quarter-hour mark when goalkeeper David Ospina clattered into Oscar as he went through on goal.
The Brazilian was nevertheless able to get a shot on target that Bellerin cleared off the line as the appeals were once again waved away.
Arsenal fans cheered when former captain Cesc Fabregas was booked midway through the first half for diving under a challenge from Cazorla, but were aggrieved when they had a penalty appeal of their own just after the half-hour mark.
Cazorla was able to get a shot away that appeared to rebound off Gary Cahill's arm at point-blank range, with the referee subsequently opting not to give the Gunners a penalty.
The first half ended with chances as Willian sliced through the Arsenal defence before setting up Ramires, who fired tamely at Ospina, while Sanchez and Mesut Ozil came close for Arsene Wenger's charges at the other end.