Anthony Gordon gave United - backed by more than 7,000 travelling supporters - the lead midway through the second half, but Sammie Szmodics levelled for their Championship opponents.

Newcastle had gone out of the Carabao Cup at the quarter-final stage on penalties at Chelsea in December, but Martin Dúbravka was their hero this time as he saved two spot-kicks, having already made a string of stops during the game and extra time.

Kick-off was delayed by 15 minutes because of queues outside the ground - an issue which seemed to affect both sets of supporters - but even when referee Jarred Gillett finally got proceedings underway, the action took some time to get going.

A Bruno Guimarães volley was blocked early on but neither side was able to fashion a clear-cut opening until the 27th minute, when Blackburn's leading scorer Szmodics passed up a great opportunity to put the hosts in front.

The Rovers frontman was slid in by John Buckley, but smashed his shot into the side-netting at the Bryan Douglas Darwen End.

Then four minutes later, Dúbravka - back in the side following illness - got a vital touch to a Thrhys Dolan drive which flashed across goal, with Szmodics racing in at the far post but frustrated by Dúbravka's intervention. The resulting corner was played to Szmodics on the edge of the area, but his powerful effort was fielded by the Newcastle netminder.

At the other end, Kieran Trippier found Sean Longstaff galloping into the box but the midfielder - whose first Magpies goal came on this ground in the same competition five years ago - saw his attempt kept out by former Darlington and Gateshead goalkeeper Aynsley Pears at his near post.

Shortly before half time, Szmodics twisted and turned to make room for a left-footed strike which Dúbravka pushed over the bar.

United were dominating possession but Blackburn arguably carrying the greater threat, and in the 52nd minute Dúbravka was again called into action to get his palms behind a Buckley shot from the edge of the area.

Just before the hour mark, Jacob Murphy had an effort deflected behind off Callum Brittain then Jamaal Lascelles' downward header from the resulting corner was cleared off the line by Kyle McFadzean.

Then in the 69th minute, Longstaff sent Gordon racing through on goal but Pears stood firm to deny the Magpies' number ten and Longstaff headed off target from the corner.

But United took the lead seconds later, when substitute Miguel Almirón cut the ball back for Gordon to sweep home his ninth goal of the campaign.

Rovers forced extra time, however, as Arnor Sigurdsson teed up Dilan Markanday. His shot hit the woodwork - but Szmodics was on hand to slot home the rebound.

In the 87th minute, Szmodics caused yet more problems for the Magpies, getting in a shot which Dúbravka was equal to. Then in the third minute of added time, United's goalkeeper brilliantly blocked with his legs from Yasin Ayari to keep his side in the cup.

In extra time, home skipper Dom Hyam thwarted Lewis Miley as the teenager looked to pull the trigger in the box, then a Fabian Schär header from a Guimarães corner dropped over the bar.

Pears made a stunning double-save in the 103rd minute, keeping out Gordon and then Longstaff from close range, and the Rovers keeper was at it again moments later to turn Lascelles' header around the post.

Gordon was next to be denied by Pears, although this time it was a relatively routine save as the keeper got his body behind the winger's long-range shot.

Somehow United failed to score in the 112th minute when Gordon took the ball round Pears and teed up Guimarães, whose shot was blocked on the line by Scott Wharton before Harvey Barnes was unable to turn the rebound home.

But the tie remained on a knife-edge and Dúbravka made another save from Szmodics at the other end, which meant penalties.

Schär converted first and Dúbravka saved from Szmodics, but then Barnes was denied by Pears. Callum Brittain scored but so did Guimarães.

Sigurdsson netted and Elliot Anderson - making his first appearance since October as a late substitute - also swept home. Ayari sent Dúbravka the wrong way but Gordon scored for Newcastle. And when Dúbravka saved Hyam's spot-kick, Newcastle were through to the last eight.