Arsenal gained one point but arguably lost two in a 1-1 stalemate with London rivals Chelsea at Stamford Bridge in Sunday's Premier League showdown.
The door had seemingly opened for the Gunners to move nine points clear at the Premier League summit when Moises Caicedo was dismissed, but Trevoh Chalobah gave the Blues a deserved lead.
The 10 men of Chelsea would have been good value for all three points, but they were forced to accept one, as Mikel Merino's header saw Arsenal end the weekend with a five-point lead at the top.
Here, Sports Mole looks at five things we learned from Sunday's stalemate.
Chelsea 1-1 Arsenal: Reece James is the real deal... when fit
Once again shoe-horned into a midfield role with Enzo Fernandez operating further forward, Reece James put in a masterful display befitting a Chelsea captain, one that was worth a man-of-the-match prize.
The England international won all six of his duels on the ground - drawing four fouls - and prevailed five of his six battles in the air too, demonstrating a tenacity that Arsenal struggled to deal with.
As is always the case with James, it is all about staying fit now, although the recent signs are very encouraging indeed on that front.
Chelsea 1-1 Arsenal: Mikel Merino is Arsenal's aerial hero
© Imago / Pro Sports Images
For much of tonight's game, Merino was largely ineffective in an auxiliary centre-forward role, but the Spaniard demonstrated exactly why he is Arsenal's emergency number nine when needed.
Merino's equalising header was simple enough, but he has now reached the 10-goal mark in the Premier League, and seven have been scored with his head.
Of all non-defenders to score at least 10 Premier League goals, the only one to score a higher ratio with their head was James Scowcroft with 71% - 10 of his 14 were netted with his noggin.
Chelsea 1-1 Arsenal: Blues' disciplinary concerns rear up again
After five games without a red card, Chelsea had ostensibly cleaned up their act, but the Blues always risked stepping over the line with their overzealousness.
When Moises Caicedo gets it right, the Ecuadorian enforcer is a master of the tackle, but he got it very wrong tonight, and a red card was undoubtedly the correct call.
Marc Cucurella's early booking also prevented him from getting too tight to Bukayo Saka too often, which played a part in the winger having time and space to cross for Merino's leveller.
Chelsea 1-1 Arsenal: Mikel Arteta's men lack a streetwise edge
For the first time on record in the Premier League - since records began in 2006-07 - Arsenal collected three yellow cards inside the opening 30 minutes of a game.
Anthony Taylor did not hesitate to brandish a booking this evening, and Arteta's men did not initially wise up to the circumstances, too often finding themselves sucked in by the more streetwise Blues and being punished for it.
Much like Cucurella's yellow, Arsenal's spate of cautions undoubtedly reined them in slightly too, and Chelsea deserve credit for playing the game on their terms for much of it.
Chelsea 1-1 Arsenal: William Saliba, Gabriel Magalhaes absence more than set-pieces
Without their two defensive rocks in William Saliba and Gabriel Magalhaes, Arsenal had little going for them in the way of set-pieces, as shown by Chalobah's deft near-post header for the opening goal.
However, without the chemistry that the pair have built up over the last four seasons, Arsenal's build-up play from the back also suffered, and the visitors ended the game having had fewer shots than their 10-man hosts.
Arteta's men were also guilty of too many misplaced passes, but the more Cristhian Mosquera and Piero Hincapie play together, the better their understanding will be.