Emile Smith Rowe made the most of his red card reprieve as the Arsenal youngster sent the FA Cup holders into the fourth round with the decisive extra-time strike in Saturday's 2-0 victory against Newcastle.

Smith Rowe avoided being sent off when his foul on Sean Longstaff -- initially ruled a dismissal -- was changed to a booking after referee Chris Kavanagh consulted the pitchside monitor.

It would have been harsh on the promising 20-year-old midfielder if he had been given his marching orders.

Smith Rowe celebrated the escape with a fine finish to open the scoring in a hard-fought third-round tie at the Emirates Stadium.

Gabon striker Pierre-Emerick Aubameyang bagged Arsenal's second goal -- just his sixth of a difficult season -- in the final moments.

"It was bit of a relief for me with the (red card) incident. It definitely wasn't intentional," Smith Rowe said.

"I'm happy to get the goal. From a young kid I have always wanted to play for this club.

"We knew how tough it was going to be. It was about breaking them down. It shows how together we are.

"We have been working off the pitch to get closer as a group."

The Gunners gave boss Mikel Arteta the first silverware of his reign when they beat Chelsea in the FA Cup final in August and the optimism provided by that success is slowly returning to north London after a difficult period.

Arteta was fighting to save his job just two weeks ago, but three successive wins over Christmas lifted Arsenal away from the Premier League relegation zone and eased the pressure on the Spaniard.

Arsenal have won the FA Cup a record 14 times, lifting the trophy four times in the last seven seasons, and another long run in the competition would be a welcome boost for Arteta.

Bernd Leno, Kieran Tierney, Pablo Mari and Aubameyang were the only Arsenal players to retain their places from the 4-0 win at West Brom.

Arsenal were forced into a late change after Gabriel Martinelli suffered an ankle injury in the warm-up and was replaced by Reiss Nelson.

Newcastle made eight changes of their own but chances were at a premium for Arsenal until David Luiz's quick free-kick found Aubameyang, whose stinging strike was pushed away by Martin Dubravka.

Andy Carroll scored his first Newcastle goal in 10 years recently and he forced Leno into action with an agile strike from the edge of the area early in the second half.

Newcastle were showing more attacking intent, only for Carroll to waste a golden opportunity to put them ahead when he stabbed wide from close range.

Joe Willock forced Dubravka to make a superb save at full stretch when the midfielder met Nicolas Pepe's cross with a glancing header.

Arsenal captain Aubameyang couldn't hit the target with a close-range header before Leno made a brilliant stop to deny Carroll in the final moments of normal time.

Arsenal broke through in the 109th minute when Bukayo Saka chipped a pass to Alexandre Lacazette and his header reached Smith Rowe, who controlled on his chest before drilling a fine finish into the far corner for his second goal of the season.

Aubameyang put the result beyond doubt in the 117th minute when he tapped in Tierney's cross.