The Magpies were twice forced to come from behind, but Barnes proved decisive against one of his former clubs as Newcastle secured their place in the third round.

West Brom took the lead in the 19th minute when Isaac Price caught Newcastle goalkeeper Antonio Jaouen out with an audacious free-kick.

Newcastle responded before half-time, with summer signing Bazoumana Touré scoring on his debut after meeting a dangerous cross from Amar Dedic.

Barnes was introduced at the break and made an immediate impact. His first effort was blocked, but he reacted quickly to fire Newcastle in front.

The visitors refused to give up, however, and Price scored his second from the penalty spot after Lewis Hall was penalised for handball.

Newcastle then pushed for the winner, with Hall hitting the post, before Barnes settled the contest with a smart finish from another Dedic cross.

The victory continued an entertaining start to Newcastle's season after their 2-2 Premier League draw with Liverpool on Sunday.

Newcastle head coach Matthias Jaissle was delighted with Barnes' contribution and also praised the performances of Dedic and Sean Steur.

The German manager also confirmed that Will Osula will undergo further scans on his foot injury as Newcastle assess his condition.

Jaissle is also keen to strengthen his squad before the transfer deadline and made his intentions clear after the win.

"Yes, I want more signings," he said. "Where? This is something I will not tell you. But yes, I will push every day for new signings."

The Newcastle boss explained that the club's transfer strategy remains focused on signing younger players with the potential to improve.

"We want to continue our brave way, not bringing in guys who are close to retirement," he said.

Jaissle was also pleased with the arrival of Nico Gonzalez, who was unveiled at St James' Park before kick-off.

"I'm very happy to see Nico become a Newcastle United player," he said. "He brings serious quality and elite experience in a key area of the pitch."

The manager believes Gonzalez can add both physical strength and composure to Newcastle's midfield.

"Nico is a really strong ball carrier - somebody who can drive the team forward while staying composed under pressure," Jaissle said.

"He also brings discipline defensively, he reads the game well and his physicality makes him well suited to the Premier League."

Sporting director Ross Wilson revealed Newcastle had been determined to complete the deal after identifying Gonzalez as their preferred target.

"This was the one we wanted, and we're delighted to welcome Nico to Newcastle United," Wilson said.

"He fits the exact criteria we set for this position and we weren't prepared to compromise on that."

For now, Barnes has ensured Newcastle can look ahead to the next round with confidence after another entertaining night at St James' Park.

The Magpies' next challenge comes against Tottenham Hotspur in the Premier League at Tottenham Hotspur Stadium on Saturday.

Kompany confirms Jamal Musiala absence as Bayern prepare for Stuttgart encounter