Substitute Kwame Yeboah has headed home a winner 17 minutes from time as Western Sydney Wanderers edged out in-form Wellington Phoenix on Friday to revive their flagging semi-final hopes.
But the Wanderers' 1-0 win at Bankwest Stadium was overshadowed by a sickening head knock for key import Nicolai Muller.
Play was held up for six minutes during the first half as Muller received attention, with multiple players from both sides waving frantically for attention from the sideline for the stricken Wanderers forward.
The German appeared unconscious before he hit the turf after a reckless lunge from Phoenix defender Louis Fenton resulted in a clash of heads midway through the first half.
Initial reports indicated Muller had suffered a badly cut lip and swelling around the jaw and cheek.
It was a rare poor day at the office for the high-flying Phoenix, who rarely got out of first gear and played the final 25 minutes with 10 men after key defender Luke DeVere was dismissed for a second caution.
The in-form Phoenix - boasting five wins from their past seven outings - started brightly, with David Ball somehow failing to open the scoring in the third minute with a shot that struck both posts but stayed out of the goal.
But that was as good as it got for the Phoenix, who barely created any further goalscoring opportunities.
Yeboah, who came on for Muller, made Wellington pay by expertly heading home Daniel Georgievski's cross to seal the Wanderers' first win in five matches since the Sydney derby in February.