The Norwegian went into the game under pressure after the 2-1 home defeat to Motherwell last week but the visitors started a bruising match — midfielder Stuart Armstrong and Dedryck Boyata were substituted after sustaining respective back and hamstring injuries, and are doubts for Dundee tomorrow — with good tempo and took the lead in the 42nd minute through midfielder Nir Bitton.
Hearts midfielder Sam Nicholson levelled in first-half added time but Celtic came out strongly at the start of the second period and midfielder Tom Rogic restored their lead with a wonderful strike in the 70th minute.
However, as the match entered added time, Gorgie striker Osman Sow took a short free-kick from Prince Buaben and his drive from 25 yards — which looked to take a slight deflection off Gary Mackay-Steven — ended behind Parkhead keeper Craig Gordon.
Celtic move a point ahead of Aberdeen at the top of the Premiership and they have played a game less than the Dons but Deila was pleased as much with his side’s response to the Well defeat.
“It was disappointing (to lose the lead twice) but what I am happy with is the good team spirit in the team.
“Against Motherwell that was disappointing, people were playing for themselves instead of playing for the team. Today I saw my old team back. I saw a hard-working team which was organised and played forward quickly and that is the way I want to see my team.”
It was difficult to see a way back for Hearts as Celtic led 2-1 in the second half. But as the match moved added time, after Forrest tripped King 25 yards from goal, Buaben slipped the ball to Sow and his drive ended up behind Gordon to stun the Hoops.
“Sometimes you have to give credit to the opponent when you have strikes like that,” said Deila. “Craig had no chance. Maybe it was a deflection but that was an unbelievable goal.”
Alexander, Paterson, Augustyn, Igor Rossi, Oshaniwa, Buaben, Djoum (Pallardo 62), Gomis (Zanatta 87), Nicholson, Reilly (King 80), Sow.
Gordon, Lustig, Boyata (Ambrose 33), Simunovic, Tierney, Bitton, Johansen, McGregor, Rogic (Mackay-Steven 78), Armstrong (Forrest 20), Ciftci