Kilmarnock secured their place in the last eight of the League Cup with a hard-fought win over Hearts.

Hearts pushed for a second-half equaliser but failed to break down a solid visiting backline.

Derek McInnes’ men will face Dundee United at home in their quarter-final tie.

Kilmarnock arrived in the capital in the knowledge they were unbeaten in their last seven visits to Tynecastle and gave an early indication of their intentions when Rory McKenzie fired in a shot that Craig Gordon had to push away.

But the Ayrshire side found the back of the net midway through the opening period when Cameron peeled away from the Hearts defence to cushion a header in from a Liam Polworth cross.

The goal appeared to shake Hearts into action and Lawrence Shankland twice came close to snatching an equaliser before the break.

Shankland’s first effort was palmed away by Walker before the visiting keeper then saved magnificently from the striker, diving high to his left-hand side to push the ball wide of goal.

The pressure continued into the second period with Josh Ginnelly utilising his pace, but his cross into the box was narrowly missed once again by the frustrated Shankland.

Kilmarnock, though, always looked dangerous with the impressive Cameron proving to be a real handful for the home defence.

And the visitors almost doubled their advantage when Ash Taylor’s header looped over Craig Gordon only four Shankland to nod the ball away off the goal-line.

Robbie Neilson introduced Ewan Henderson, Gary Mackay-Steven and Connor Smith but the Kilmarnock defence remained intact with Taylor leading his team into the quarter-finals with a fine defensive display.

Kilmarnock manager Derek McInnes: “I was pleased with a lot of aspects of the performance. We spoke about the importance of getting a strong start.

“Equally we wanted to make sure we got the first goal. I thought we had so much energy and discipline. I’m delighted we got the win.”