Superb Joe Lewis saves denied Hearts a win in their first league game at their temporary Murrayfield home – and first under Craig Levein as manager.
Aberdeen needed a win to return to the top of the Scottish Premiership and the point leaves them behind holders Celtic on goal difference.
The Dons had more possession before the break but had Lewis to thank as the keeper denied Isma and Jamie Walker.
Hearts dominated after the break and Isma also fired against the crossbar.
So Levein’s second spell as Hearts team boss begins with a draw but a promising performance against last season’s runners-up.
Derek McInnes’ Dons lose their 100% league record this season but extend their run of games without a defeat against Hearts to five.
This was a fine spectacle in the capital, a big crowd in the Murrayfield sunshine and a game that was intriguing all the way through.