Stefan O'Connor
Stefan O'Connor made his Arsenal first-team debut against Galatasaray in the Champions League last seasonGetty

Arsenal defender Stefan O'Connor has joined York City on loan until 6 January after impressing for the Gunners youth team in the U19 Uefa Youth League. The youngster made his first-team debut for the north London club in the Champions League against Galatasaray last season.

"Young defender Stefan O'Connor has joined League Two side York City on loan until January 6, 2016. Everyone at the club wishes Stefan well for his time with York City," a statement on the Gunners' official site read.

Arsene Wenger handed the 18-year-old defender a chance with the first-team after his impressive displays for Steve Gatting's U18 side last season. O'Connor, who is primarily a centre-back, played at right-back for his debut, and despite being out of position, the manager was impressed with his display.

The Arsenal youngsters have already qualified for the next stage of the U19 Uefa Youth League following home wins over Olympiacos and Bayern Munich, and O'Connor was a key member of the squad. They have one more game against the Greek club away from home, but the defender is certain to return when the knockout phase competition resumes in 2016.

O'Connor is the 12th Arsenal player to be loaned out this season, following the departures of Carl Jenkinson, Chuba Akpom, Isaac Hayden and Gedion Zelalem among others at the start of the season.

Per Mertesacker, meanwhile, has called on the team to keep their focus ahead of their clash with Norwich City on Sunday (29 November) as they look to bounce back from the loss against West Bromwich Albion in their last league encounter. The German World Cup winner wants the team to emulate their midweek display against Dinamo Zagreb in the Champions League, which saw them runaway 3-0 winners.

"Every Premier League team deserves credit because they do so well. You cannot go to Norwich without purpose. We need to play serious football and attack well like we did against Zagreb, and then we have a good chance of keeping our hopes alive for the league," Mertesacker said, as quoted on Arsenal's official site.