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Southampton put Arsenal to the sword, winning comfortably 4-0 at St. Mary's on Saturday to end the Gunners' six-game unbeaten streak across all competitions. A wonder strike from Cuco Martina started the parade and second half goals from Shane Long and Jose Fonte padded the result. In truth, Southampton could have had a few more.

This was a blow to Arsenal's title hopes as the result denied the Gunners a slot atop the table after Leicester lost earlier in the day to Liverpool. It will also surely revive the debate over the Gunners' resilience: the Gunners were carved apart on the day in an ugly repeat of a memorable match last season, and looked nothing like the side that had schooled Manchester City only a game prior.

Arsenal knew they could go top at kickoff, but as has so often been the case for the Gunners, when presented a gift, they spurn it. St. Mary's has not been the most fertile of grounds, of course: last time the two sides met here – New Year's Day – the Saints ruthlessly punished two bad errors from then starting keeper Wojciech Szczesny, winning out 2-0. The margin could have been far greater in that match (after the game an angry supporter memorably confronted Arsene Wenger) and prior to this game, Wenger allowed as how he had not forgotten the match or the result, but he claimed his defense was now stronger.

If his defense was stronger, that fiber was not in evidence today. In fact, Arsenal failed to settle in at all, and looked a jaded side, more content to move the ball sideways than go forward. They could have conceded six goals today, and were lucky not to.

So, Wenger certainly must have been suffering flashbacks when Martina lashed in what will perhaps stand as the goal of the day, a belter from 30 yards that curved around the entire defense in the 21st minute to nip in at the far post. The goal came out of nothing, a routine header out from Per Mertesacker, and it was difficult even to credit Martina with a proper shot so speculative was the take. But it was a brilliant hit and it gave the Saints a not entirely undeserved lead.

Arsenal's shaggy play immediately continued with Laurent Koscielny nearly gifting the Saints a second in the 28th with a ludicrous backpass that nearly set up Steven Davis for a tap-in.

The Gunners didn't really challenge Maarten Stekelenburg save in fits and starts. Nacho Monreal had a fine chance in the 17th minute when a looper from Mesut Ozil fell to him at the far post in space; Theo Walcott had a left-footed shot smothered in the 36th, and then saw a free header hit the wrong side of the net off a corner moments later.

The best chances continued to be Southampton's. A lazy clearance allowed Long in free on Petr Cech, but a ball that was easier to poke into a gaping net was instead punted into the Itchen. The Saints continued to boss the game, with Virgil van Dijk clattering into Cech and heading home in the 50th minute, only to see the goal written off for offside. It was perhaps a marginal call but it stood – but the Saints would soon double their lead.

Long, who had tormented the Arsenal back four for much of the match, finally had a goal to his credit in the 56th off a frankly dirty play. Long kicked out at Koscielny, tripping him up and allowing him to go through clear to the far post to receive Sadio Mane's pass to score with ease. Southampton had clearly been the better of the sides – but that was again a poor call by ref Jon Moss, who endured a miserable afternoon.

Jose Fonte then put the game out of reach with just over twenty to minutes to play when he bundled home a header from close range. It was a bullet of a strike off a corner from Ryan Bertrand – but Arsenal's entire defense stood and watched the goal fly in. By that time, of course, the game was over as the Gunners rarely looked like scoring. Their day was summed up when Mesut Ozil nearly grabbed one back with ten to play, only to see the ball spin off the line and away.

Long added a capper in stoppage time, sliding the ball through Cech's legs for an easy goal. Long started the play in a clearly offside position, but the linesman allowed the goal to stand anyway, perhaps in recognition of the fact that Long had moments earlier pinged a shot off the far post.

Arsenal must now dust themselves off ahead of a three-game home-stand against the league's lesser lights: Bournemouth, Newcastle and then Sunderland in the FA Cup. Southampton probably have a trickier test as they head to London to meet West Ham Monday ahead of games against Norwich and Palace.