Bacary Sagna proved his worth in Arsenal's crucial 1-0 win at Sunderland. The French right-back inspired an heroic defensive effort, despite playing out of position.

Sagna was thrust into a central defensive role, thanks to a late injury to Laurent Koscielny. The full-back acquitted himself superbly alongside Per Mertesacker at the heart of Arsenal's defence.

Sagna was particularly strong after the Gunners already patchwork defense had been weakened further by the sending off of Carl Jenkinson. The young Englishman was filling in for Sagna at right-back. He was dismissed with a little over an hour gone, after a wild lunge at Stephane Sessegnon.

However, the Black Cats couldn't make their numerical advantage a decisive one. That was because Sagna turned away most of their promising attacks. He was smart, athletic and aggressive, all the qualities that usually epitomise the France international at his best.

Yet those qualities have been in short supply this season. Normally Arsenal's "Mr dependable," Sagna has been guilty of more than a few woeful performances this campaign. He has often been slow to track back from attacking positions and has been hesitant defensively.

Motivation, or lack thereof, has often been claimed as the root cause of Sagna's malaise. This theory does have some merit, based on Sagna's withering critique of Arsenal's summer transfer dealings. The ex-Auxerre star was critical of the club's decision to sell high-profile duo Robin van Persie and Alex Song.

This dissatisfaction, coupled with Sagna's own deal expiring in 12 months, seemed to suggest he was ready for the exit. However, his resolve at the Stadium of Light showed a player still committed to the Arsenal cause.

The Gunners certainly need him. Sagna's heroics keyed a vital win that lifts Arsenal, albeit temporarily, to fifth in the English Premier League. More importantly, it means they remain within four points of fourth place and entry to next season's UEFA Champions League.

Securing that coveted spot will require all of the defensive skill of experienced players like Sagna. At his best, he is an accomplished stopper. His pace is always an asset, but Sagna's anticipation and precise tackling are vital. Particularly for a defense often culpable of rash choices and calamity.

Those qualities were on display regularly at Sunderland and Arsenal need more defensive performances of this calibre. They have now kept consecutive clean sheets in the league. They may have come against Sunderland and Stoke City, two teams almost allergic to finding the net, but consistency breeds confidence.

The Gunners aren't short of goals, either along their forward line, or in midfield. However, only improved defensive solidity will lift them above Everton and Tottenham Hotspur in the race for fourth place.

In a season otherwise marred by sluggish performances, Sagna reminded Arsenal how valuable he can be to that defence.