Ryan Porteous fired Hibs into the lead three minutes after the break and Curtis Main was sent off soon after.

Christian Doidge passed up three golden chances to extend the lead.

And Cosgrove, who had been fortunate to escape a second booking, rose to head home from a Niall McGinn corner before a late red card for Lewis Ferguson.

It denied Hibs their first Scottish Premiership win since the opening game of the league season, while Aberdeen slip four points behind third-top Motherwell but remain fourth.

Red cards and stuttering ambitions

Despite sitting in a potential Europa League qualifying place, Aberdeen went into the game amid talk of a fans protesting outside Pittodrie after last week's 5-0 thumping by Rangers which suggested a slide in their fortunes.

Hibs started second bottom and without a win over 90 minutes in nine games but with signs of recovery after securing a League Cup semi-final place and drawing with reigning champions Celtic.

However, after a point apiece, it remains worrying times for two sides with ambitions to finish at least third in the Premiership.

Aberdeen manager Derek McInnes was philosophical ahead of kick-off about the mounting pressure, pointing to a string of injuries and hopeful that the return of Scotland centre-half Scott McKenna and Andrew Considine would tighten up a leaky defence.

Had Doidge not displayed such ineptitude when through on goal four times, Aberdeen would have surely suffered what would have been their only home league defeat of the season.

His first came in the opening minutes from Daryl Horgan's through ball, but goalkeeper blocked the striker's half-hearted shot with his chest.

Neither side seriously threatened again until centre-half Porteous, back from suspension for Hibs, pounced on a deflected Tom James shot to fire home three minutes after half-time.

The home side were down to 10 men shortly after when Main lunged into Stevie Mallan, who recovered to help set up a series of chances for Doidge.

Three times the striker was denied by Lewis as Hibs became increasingly nervous as they attempted to defend a lead made less secure by the introduction of Aberdeen substitutes McGinn and Jon Gallagher.

Cosgrove looked to have a kick out at Glenn Middleton after the striker lunged into challenge the Hibs winger, but referee Don Robertson's decision not to show a second yellow card meant the Englishman was free to rise above Porteous and head the equaliser.

Ferguson's red card for a lunge on Mallan made little difference with the final whistle sounding seconds later, with the home side seemingly suggesting that the Hibs midfielder had made the most of the challenges.

McInnes and counterpart Paul Heckingbottom should be more concerned about an untidy affair between two sides struggling to rise to expectations.

Man of the match - Ryan Porteous

We are not spoiled for candidates, but Hibs scorer Porteous gets the nod,

This was a gritty, physical game, right up his street and he revelled in the battle, standing up to the combative threat of Aberdeen's towering front two of Cosgrove and Main.

The Scotland Under-21 centre-half proved his worth at the other end with the goal, a never-say-die attitude that was central to Hibs securing a crucial point.

Manager's mentality and missed chances

Aberdeen assistant manager Tony Docherty: "I'd like to talk about our reaction to going down to 10 men, 1-0 down at home, there's a lot of question marks for the players.

"There was a real inspirational period in the game where we actually could have went on and won it and that is just down to the players' mentality and personality. That speaks volumes in terms of what the manager is putting forward to make sure we're always bang at it and always all for the cause."

Hibernian head coach Paul Heckingbottom: "It's beginning to be the same story. We were good, excellent with and without the ball, stood up to Aberdeen's threats. It's a story of missed chances, should have put the game to bed, and it would have been an easy run-in.

"Credit to Aberdeen, they made the subs and went for it, but even then, they weren't really creating anything and it's a set-play that's cost us."