Alexis Sanchez
Sanchez took his tally to nine goals in his last five games ahead of the resumption of Arsenal's season.Getty Images

Arsenal forward Alexis Sanchez defied concerns over his fitness after producing a match-winning display to help Chile overcome Peru 4-3 in Lima and maintain their 100% start in World Cup qualifying. The 26-year-old scored twice in the first half, taking his tally to nine goals in the last five games, to make it two wins from two for Jorge Sampaoli's side.

Sanchez netted after just seven minutes following Mauricio Isla's pass before Jefferson Farfan's double, either side of Peru winger Christian Cueva's red card, put the home side ahead. But Eduardo Vargas and Sanchez netted before the break, before Vargas, who plays his club football in the Bundesliga with Hoffenheim, scored again just after the break to put the visitors two up. Paolo Guerrero reduced the deficit – and matched Peru's all-time scoring record late on – but they were unable to complete their comeback.

"The fact is we won on a very difficult pitch, with a very good team against us," Chile boss Sampaoli said. "We took the lead, then went behind, but we had the courage, calmness and football to turn the scoreboard [back in our favour].

"After going 4-2 ahead we were a little unsure and we wasted a few chances. Peru's home advantage will be very difficult for anyone. I think very few teams will win here and that enhances our chance and gives us hope for what lies ahead. We have progressed in style."

It was Sanchez's second 90-minute appearance in a few days, after he started the 2-0 win over Brazil on Friday (9 October), and it comes after the player had initially been considered a doubt for the international double-header having limped off with a groin injury during Arsenal's win over Manchester United. The Gunners are two points behind Manchester City after eight games, but injuries to Sergio Aguero and David Silva during the international break threaten to derail the leaders' campaign.

Sampaoli admitted after the game he had risked Sanchez's fitness against Brazil, but the fact he has come through both games injury free is a huge boost for Arsenal ahead of the resumption of their season. "Alexis also arrived not at the top of his form, with pain in the adductor," he admitted. "He couldn't play at 100%, but we thought that, for us, him not playing would give too much advantage to our rivals because his presence in our team makes things difficult for our opponents."

Sanchez will return to Arsenal ahead of a pivotal week in their season. The weekend's Premier League trip to Watford is followed by a crucial Champions League tie at home to Bayern Munich and then the visit of Everton.