The Bafana Bafana star was handed his ninth straight start after playing a major role in their narrow win over Antwerp last weekend.
Vincent Kompany's charges were creating a lot of chances in the early exchanges but were kept at bay by the brilliance of goalkeeper Simon Bolat between the sticks.
Michael Bermudez finally broke the deadlock for the visitors on the stroke of half-time with a half-volley at the near post under the body of the diving Bolat after a cross by Yari Verschaeren.
The sides were cancelling each other out in the early exchanges of the second stanza but Tau had a chance to double Anderlecht's lead in the 65th minute after receiving a cross from Bermudez inside the six-yard box but he guided his header wide.
After being booked in the first stanza, Tau was substituted in the last ten minutes and made way for midfielder Josh Cullen came.
The visitors were made to pay for not killing the game in the closing phase, as Roman Yaremchuk snatched the equaliser for Gent in the last minute with a header from close range, handing Gent a share of the spoils.
