Arsenal scored three times in the final 20 minutes as they wiped out a 3-0 deficit and claimed a point in a thrilling match at Bournemouth.
Olivier Giroud -- whose 'scorpion' goal had made headlines in the weekend win over Crystal Palace -- rose at the far post to glance home a 91st-minute leveller against a home side reduced to 10 men with eight minutes to go.
Bournemouth made a high-tempo start but it was Arsenal who threatened first when Alexis Sanchez played in Hector Bellerin and his cross was well dealt with by Nathan Ake.
Soon afterwards, Aaron Ramsey was almost threaded through by another Sanchez touch -- but the home side hit back and tested visiting goalkeeper Petr Cech with a Junior Stanislas strike from range.
Cech got to a through ball just ahead of Cherries striker Callum Wilson, who went down under the keeper's challenge but saw his appeals for a penalty waved away.
But Bournemouth were in front after 16 minutes when Stanislas sprayed a fine pass from right to left to find Charlie Daniels in space, and he beat Hector Bellerin before placing a cool finish beyond Cech.
Within four minutes, things had gone from bad to worse for the Gunners as a clumsy Granit Xhaka push on Ryan Fraser gave Bournemouth a penalty that Wilson dispatched to put the hosts two up with only 21 minutes played.
Arsene Wenger's side then suffered yet another setback as Francis Coquelin sustained what looked like a hamstring injury and was replaced by Alex Oxlade-Chamberlain.
Ramsey saw a deflected effort fizz wide as the visitors looked for a way back into the match before Harry Arter miscued an effort from the edge of the area as the home side dominated.
Alex Iwobi missed a chance to pull one back before the break when he scuffed wide from Oxlade-Chamberlain's low cross before, with almost the last kick of the first half, Stanislas whipped in a shot that bounced wide of Cech's near post.
Bournemouth survived a scare early in the second period when Iwobi and Sanchez combined before the latter's attempted cross pinballed off a series of players and was hacked clear.
Ramsey almost found a way through after neat link-up play with Olivier Giroud, but Wenger soon had another cause for concern as Giroud went down in pain after King accidentally caught him on the ankle.
The striker, fresh from his stunning 'scorpion' goal against Crystal Palace on Sunday, was able to continue after treatment.
After 56 minutes, an Arter blast from the edge of the box deflected in off Wilson, but the referee judged that it had hit the Bournemouth striker on the hand on its way in.
But the Cherries did not have to wait much longer for a third goal, with Fraser taking advantage of a slip by Bellerin -- who appealed in vain for a push -- before firing the ball between the legs of Cech and inside the far post from a narrow angle.
Stanislas then forced a good save with a whipped free kick from 25 yards before another Fraser run ended with a cross that deflected into the side netting.
Fraser ran through again before being denied by a last-ditch challenge -- but Arsenal pulled one back with 20 minutes to play when Giroud flicked on a cross and Sanchez dived to head home at the far post.
Giroud fired straight at the goalkeeper soon afterwards, only for Arsenal to turn the mood on its head as they got another goal back with just over a quarter of an hour to play.
Substitute Lucas Perez, who had come on for Iwobi a few minutes earlier, had plenty to do when the ball was flicked on to him at an angle on the left of the penalty area -- and he did in in style, burying a superb volley to set up a thrilling finish.
Dan Gosling could have wrapped things up for Bournemouth with eight minutes left, curling wide of the post after making room for himself inside the area - and within moments the hosts were down to 10 men when captain Simon Francis clattered into Ramsey and was shown a straight red card.
Ramsey shot wide for the Gunners as the game entered its final five minutes, and in the first minute of six added on the visitors completed their incredible comeback when Giroud rose at the far post to guide a header past Artur Boruc.
Arter had one last chance to restore Bournemouth's lead -- but Cech repelled his firmly-struck shot and a remarkable game ended with honours even.