Sanchez on the double as Wenger has reason to celebrate

He has drifted away from his best self this season, seemingly distracted, disaffected and counting down the games before he can leave Arsenal, whether that is next month for money or in the summer for free.

But here at Selhurst Park, in the bitter cold and quite out of the blue, he gave a ferocious reminder who he is, what he can do and how good he can be.

No one was expecting it at 1-1, with Arsenal just having conceded an equaliser to Andros Townsend, wondering how to get back into the game.

Then, Sanchez smashed in his first, stabbed in his second and four minutes later Arsenal were 3-1 up. James Tomkins nodded in a consolation but Arsenal hung on for the win.

It was Sanchez's first brace for more than seven months, his best moment of a season in which he had scored six goals before last night.

Arsene Wenger had promised beforehand that his days playing three centre-backs were over and that Arsenal were now an attacking assertive back-four team again.

But for this match Wenger reached back for the security of his back three, dropping Alex Iwobi to give Calum Chambers his first Premier League start for 16 months.

It was a cautious measure from Wenger - unusually so from a man who said his dream would only be to play with one defender.

Arsenal, quite naturally, dominated possession against a Palace team limited to fast breaks forward and hopeful shots from long distance.

The task for Arsenal was to pick their way through Palace's rigid two banks of four.

PASSING

It took some time, in the cold, for them to find the rhythm of their passing, but Palace never did much to disrupt them either.

One sharp move ended with Scott Dann blocking Granit Xhaka's shot but soon enough Arsenal were ahead, benefiting from just having enough bodies in the box together.

Jeffrey Schlupp tried to head out Ozil's free kick but the ball came back to Alexander Lacazette on the right hand side of the box.

Julian Speroni could palm away his curled shot, but only into the path of the Shkodran Mustafi, who was sharp enough to slide the ball past Martin Kelly and into the net.

Arsenal had plenty of openings after that to score that crucial second goal but it never quite broke for them.

Twice Ozil got on the end of Sanchez passes, but the first time Speroni saved, the second Kelly forced him off the ball.

This inefficiency is Arsenal's current curse and it cost them just four minutes after the restart as they conceded a painfully preventable equaliser.

Schlupp knocked a pass down the left to Zaha, running into the corner with nowhere to go. But he span sharply, confronting Chambers, who did not get tight enough to him.

Zaha made some space with a stepover and darted down to the byline. He crossed the ball - too easily - with his left and Townsend popped up, unmarked inside the box, to put the finish into the bottom corner.

This was the moment, back to square one and with the momentum against them, that Arsenal needed one of their senior players to seize the game back. And no-one better for it than Sanchez.

His first goal, putting Arsenal back in the lead, was all about power and audacity.

Lacazette held up the ball just inside the box, teeing Sanchez up and he drove it the fastest way to goal - through James Tomkins' legs, through Speroni's out-stretched glove and into the bottom corner of the net. The Chilean's second, four minutes later, was about foresight and precision.

Wilshere had the ball in the centre circle so Sanchez sprinted in behind, trusting his team-mate to find him with his pass.

Sure enough, the pass was perfect, and Sanchez took it on his right thigh and touched it into the net.

It was the introduction of Bakary Sako, of all people, who almost got Palace back into the game. He gave them an extra presence up front, curling one shot over and then having another deflected just wide.

From Townsend's corner, Tomkins got up in the box and nodded the ball in.

That gave Palace four added minutes to make it 3-3 but Arsenal, having let one lead slip, were not going to do it again. (© Independent News Service)