After a closely-fought first half, Christian Atsu netted a superb free-kick to give the Magpies the advantage in the Welsh capital.

Ten minutes later, Isaac Hayden rifled home from 20 yards to put Rafa Benitez’s side in a commanding position – just the midfielder’s second goal of the campaign.

Roared on by more than 4,000 travelling supporters, United – for the most part – looked comfortable late on, keeping the pressure on Sky Bet Championship leaders Brighton & Hove Albion.

The Seagulls will wrap up the title with victory over Bristol City on Saturday, but anything less will see the race for the crown go down to the last day.

Having struck the Magpies’ second in Monday night’s promotion-clinching win over Preston North End, Atsu was almost back on the scoresheet within moments of kick-off at the Cardiff City Stadium.

He gathered Mohamed Diame’s pass before skipping past the challenge of Jazz Richards, and only a fine block from Bruno Ecuele-Manga prevented the Ghanaian’s low-struck effort from nestling in the far corner.

At the other end, Aron Gunnarsson tried his luck after cutting in from the left, but the midfielder’s daisycutter was gathered by Rob Elliot.

Sean Morrison looked to have headed Cardiff in front after meeting Peter Whittingham’s corner 20 minutes in, but referee Graham Scott spotted a foul on Ciaran Clark in the build-up.

The home side continued to pose a threat, and just after the half-hour mark, Morrison forced Elliot into a low stop after Whittingham played a corner short to Craig Noone.

Then, out of nowhere, the Magpies opened the home side up in an instant. Diame picked out DeAndre Yedlin’s run with a defence-splitting ball, and the American’s vicious effort was parried by Allan McGregor.

Two minutes later, Chancel Mbemba met Atsu’s corner first-time, hitting the ball into the ground and narrowly over the crossbar.

With the Magpies growing into the game, Mbemba then turned provider. Left with time to whip in a cross from the right, he found his fellow centre-half Clark deep inside the area, who just failed to keep his header on target.

Early into the second half, however, it was the home side who should have drawn first blood. Joe Bennett’s cross was only half-cleared by the Magpies, but Noone – perhaps with more time than he realised – sliced wastefully wide of Elliot’s near post.

After surviving a scare, Newcastle responded quickly, and the deadlock was broken just five minutes later.

Atsu engineered room to shoot on the very edge of the penalty area, but was tripped before he could do so. After getting back to his feet, the wide-man curled beyond a flat-footed McGregor and into the net.

Just after the hour-mark, he took aim again, running at the Bluebirds’ backline before hammering high of the target.

It wasn’t long before Newcastle did double their lead, though.

Cardiff stood off the advancing Hayden 25 yards out, and the midfielder let fly with a left-footed strike which swerved past McGregor and into the bottom corner.

Neil Warnock’s side ought to have pulled one back almost instantly, as Ecuele-Manga – left unmarked – planted Noone’s corner over the crossbar from a central position.

Another chance came and went for the hosts as frontman Kenneth Zohore headed Bennett’s inviting cross over the top 12 yards out.

Cardiff ‘keeper McGregor then denied United a third, blocking Aleksandar Mitrovic’s low-struck effort with an outstretched leg.

Noone wasted another opportunity for the Bluebirds late on, before Jonjo Shelvey called McGregor into action once more during an entertaining finale.

There was to be no further drama, though, as Newcastle bettered the feat achieved by Kevin Keegan’s crop a quarter of a century ago.