Western Sydney Wanderers moved back to within four points of the A-League top six with a 1-0 victory over Wellington Phoenix on Friday.

A header from Kwame Yeboah with 17 minutes of normal time left secured all three points at Bankwest Stadium after Luke DeVere had earlier been sent off.

Phoenix, already assured of a Finals place, were hoping to consolidate second spot but only mustered one shot on target throughout the contest, although they were cursing their luck early on when David Ball's effort struck both posts but did not cross the line.

The first half was overshadowed by a serious injury suffered by Nicolai Muller, who is expected to have concussion after a clash of heads with Louis Fenton.

Momentum swung the Wanderers' way when DeVere was given a second yellow card for tripping Yeboah, and it was the man who came on for Muller who proved the matchwinner, heading home Tate Russell's cross.

Wanderers are four points behind sixth-place Adelaide United, with a game in hand, although Western United are level on 30 points after playing two games fewer.