In the aftermath of Arsenal's recent defeat to Tottenham at White Hart Lane, no one gave them a chance of finishing in the top four.But not even two weeks on and they're now firmly back in the race for Champions League football following a vital win over Southampton on Wednesday night.Goals from Alexis Sanchez and Olivier Giroud secured a second successive 2-0 win to put Arsenal fifth and only three points behind Manchester City in fourth.The Gunners also have a game in hand over Liverpool, who they are currently four points behind but can close the gap to one.It was Sanchez who once again broke the deadlock for Arsenal, the Chilean fooling two Southampton defenders after Mesut Ozil's pass and firing past Fraser Forster.Giroud then added a second to kill the game with seven minutes remaining. Sanchez played a delightful cross for Aaron Ramsey, who headed back across goal for Giroud to head home.Victory at St Mary's Stadium was Arsenal's fourth in five league games, which puts them in good stead ahead of Saturday's trip to Stoke City.Arsene Wenger's men can ill afford to drop any points in their three remaining fixtures, with home games against Sunderland and Everton also in the offing.Arsenal fans were understandably sceptical heading into the clash with Southampton, who memorably beat the Gunners 4-0 last season.But in their new 3-4-3 formation, Arsenal looked solid and produced a performance worthy of victory.Sanchez provided the game's moment of magic (again), but it was his celebration that really caught attention amongst the club's supporters on social media.In the video below, Sanchez beats Forster to open the scoring and then runs over to Arsenal's travelling fans before slapping the badge on his shirt.There's been a lot of speculation about the Chilean's future recently but his celebration was yet another reminder of how, despite this season's shortcomings, he loves Arsenal.

SANCHEZ'S GOAL AND CELEBRATION

Sanchez's celebration inevitably sent Arsenal fans into meltdown and gave them renewed hope that he will stay in north London this summer. Here's how Twitter reacted.

TWITTER REACTS

Speaking after the game, Wenger hailed Sanchez for his virtuoso performance: "That's Alexis. He's a player who never gives up and is always tricky to stop, he's very good in short spaces.

"Once he has the ball in the box, he's dangerous. Alexis always grows during the game. He's always a slow starter and gets stronger and stronger."