Derek McInnes insisted his side are not finished in the title race after losing to rivals Rangers at Ibrox.
Hearts still have a two-point lead at the top of the table, although Celtic are three behind with a game in hand. It should be noted that McInnes' side currently have a better goal difference than the reigning champions.
"We still feel, although we've lost a fight today, there's still a war to win and we're still well in it," McInnes said after the 4-2 loss to Rangers.
"For us to be top of the league at this stage of the season is testament to the efforts of the players. And I've seen enough today that there's still a lot of fight and courage about our performance."
Some pundits have suggested Hearts have the easiest run in before the split, as Celtic and Rangers are due to play each other on Sunday 1 March (12:00) at Ibrox.
The Gorgie side have four home fixtures coming up in the six games pre-split: Falkirk (H), Aberdeen (H), Kilmarnock (A), Dundee (H), Livingston (A), and Motherwell (H).
"We've now got some good games on paper coming up and it's important that we try and maximise the games coming up," McInnes said.
"And hopefully, as I said, going into the post-split games, when we play Rangers and Celtic again, there's still a fight to be won."