It was Onyewu's seventh league goal in 99 games for Standard Liege. The win last weekend was its 19th of the season and, with 10 ties, Standard Liege remains undefeated. Its nearest rival is Anderlecht.
Heerenveen, with Bradley going the full 90, came from behind to win at Willem II, 3-2.
The second- through fifth-place finishers in the Dutch Eredivisie play off for one Champions League spot. With two games left, Heereneveen is in fifth place, ahead of sixth-place Feyenoord thanks to a superior goal difference.