Brazilian 18-year-old Gabriel Martinelli started and finished the scoring at the Emirates Stadium with his first Arsenal goals on his full debut, with academy graduates Joe Willock and Reiss Nelson also on target after Emery changed his entire starting XI for the tie.

Speaking about Holding, who was injured at Manchester United on December 5, Emery said: "Every day in training he helps us to have more performances like a team. He needed to take minutes, take confidence.

"And I think tonight – the first match after playing with the under-23s – is perfect. He was a little tired at the end of the match but he scored and he's happy tonight and we're happy for him."

Emery used the fixture to hand a debut to £25million summer signing Kieran Tierney, available after arriving from Celtic with a groin problem, while substitute Hector Bellerin joined Holding in returning from a long-standing knee issue.

Bellerin marked his return with the assist for Willock's goal, moments after replacing impressive left-back Tierney in the 77th minute.

Despite losing 19-year-old forward Emile Smith Rowe to a first-half head injury, Emery was left to reflect on an extremely positive evening.

He said: "It was an opportunity for different players to take confidence, to take minutes. The game was for us in 90 minutes very consistent.

"Some different players gave us the performance, also coming back after injuries of Holding, Kieran Tierney, Hector Bellerin.

"And I think it was a good match, a good result, a clean sheet, there are a lot of pleasing things and we can be positive with different options for the next matches."

Speaking about Smith Rowe, he added: "It was for a precaution we changed him. I'm thinking he's not going to be a serious problem."

Emery was also left purring at the performance of Martinelli, whose only previous appearance since joining from Brazilian club Ituano in the summer was a six-minute cameo at Newcastle on the opening weekend of the season.

"Martinelli is a very young player but he came here and we were waiting and watching him, how he could improve with us," said Emery.

"He played very well. He was working each training with a big spirit and with a big performance.

"I spoke with him to have some patience to get his opportunity to play, to do like he was doing in training and in the matches in pre-season and tonight he did that and really he deserved it because he's a very humble player.

"He fights, he is hungry to have that opportunity to help us and his work was perfect tonight."

Nottingham Forest boss Sabri Lamouchi, who suffered a first defeat since the opening weekend of the season, admitted his side were second best but felt the final scoreline flattered the hosts.

Forest, backed by almost 8,400 fans, managed only one attempt on target in 90 minutes in their first visit to Arsenal since a 2-1 top-flight loss in August 1998.

"We deserved to lose but five, for me, is too much," said the Frenchman.

"You play tonight against one of the best four, best six teams in the Premier League, top players. Nothing to add.

"Congratulations to Arsenal and good luck for the rest of this competition."