Mikel Arteta revealed "there has been a great energy" around his Arsenal squad following their dramatic win against Newcastle United on Sunday.

The Gunners scored two late goals through Mikel Merino and Gabriel Magalhaes to secure a 2-1 victory at St. James Park, leaving them two points behind Premier League leaders Liverpool.

It was the second-latest time that Arsenal trailed in a Premier League game and went on to win (equalised in the 84th minute), after their 3-1 win over Norwich City in April 2013, when the equalising goal was converted by Arteta himself (85th minute).

The mood around the training ground would have also been lifted after William Saliba's new contract extension was announced on Tuesday, with the French defender committing his future in north London until June 2030.

Despite their hard-fought victory, Arteta has already turned his attention to Wednesday's Champions League fixture against Olympiacos.

"There has been great energy. The moment you went in the dressing room, everyone was celebrating because of the manner and the way it happened," said Arteta.

"But you have to move on immediately, and we know we have a very tough match against Olympiacos, and we are ready for it."

Arsenal started their European campaign with a 2-0 away win over Athletic Bilbao, but welcome Olympiacos to the Emirates Stadium for their first home match.

Ahead of the second matchday, the Opta supercomputer predicted that Arsenal are second-favourites to win the competition, after Liverpool.

Having reached the semi-finals last season, losing to eventual winners Paris Saint-Germain, Arteta wants to go even further this time around.

"We have the same ambition, which is to go game by game and try and be better than the opponent, which is very difficult in this competition. We want to win as many games as we can," Arteta added.

"[Olympiacos] is going to be a really difficult one. We know how important the home form is going to be to reach where we want to arrive, and tomorrow we have the opportunity to start well."