Uche Ikpeazu was challenged by Gary Harkins after Thistle's Christie Elliott had cancelled out Christophe Berra's opener for Hearts.

But referee Bobby Madden allowed play to continue, much to the Hearts manager's chagrin.

"I don't understand how we didn't get it," said Levein, whose side will host Thistle in next Tuesday's replay.

"I've had a look at the penalty claim. It's a certain penalty.

"I think Partick's goal was their first shot on target in the match so that tells you the story of the game. We had loads of domination but we didn't make enough chances and certainly we didn't score enough. We also hit the bar twice in the second half.

"We're still in the cup competition, that's the most important thing. I'd always fancy us at home."

The eventual winner of the tie will face Inverness Caledonian Thistle in the semi-final at Hampden but Thistle boss Gary Caldwell, whose side are currently bottom of the Scottish Championship, was keen not to look beyond the replay.

"We've still got a huge task in front of us," said the former Scotland defender.

"We scored a fantastic goal and thoroughly deserved the draw. It's difficult from open play to score goals and to break down a team of that quality with international players at the back, it has to be great passing, great movement.

"A draw was a fair result and we look forward to next week. It's a difficult place to go but I believe we've got a group of players that can stand up to that."