Arsene Wenger hailed Alexis Sanchez's unique qualities after the Chilean opened the scoring in Arsenal's 2-0 victory at Southampton and then created a second goal for substitute Olivier Giroud.

Wednesday's victory took Arsenal to within three points of the Premier League top four and keeps alive the possibility of a 20th successive season of Champions League football for the north London club.

Sanchez broke the deadlock in the 60th minute at St Mary's, gathering Mesut Ozil's pass and leaving two defenders sprawling before firing home his 20th goal of the league campaign.

"The goal he scored tonight shows what he's about: very good technique in a short space," Wenger said.

"He scores important goals. He has invention in his head. He's creative, not phased by anything, and he surprised everyone in the stadium tonight with his goal.

"Everyone was expecting him to take a shot, but he's very quick on the move."

It was Sanchez's cross that Aaron Ramsey headed back across goal for Giroud to nod in the visitors' second goal in the 83rd minute.

"Giroud came on and the second goal was very important for us, too," Wenger added.

"We had to (dig deep) because Southampton started at a strong pace. The first half was quite even, but we were focused and determined.

"I felt if you look at individual performances you couldn't be disappointed from the goalkeeper to Danny Welbeck. Everybody played well."

Now Arsenal must keep the pressure on the top four by showing the same focus and winning their three remaining matches, starting at Stoke City on Saturday.