Blackburn were hoping to celebrate Tugay's 294th and final appearance for the club with a victory but they could only end their campaign with a goalless draw against already-relegated West Brom.
Instead the home supporters were left debating the second-half dismissal of striker Jason Roberts 10 minutes after he stepped off the bench.
Chris Samba and Chris Brunt had already hit the woodwork when Roberts was red-carded by referee Mike Jones for an apparent off-the-ball incident with Jonas Olsson.
But the official's decision left most people baffled, not least manager Sam Allardyce, who shook his head in bewilderment.
With Blackburn safe and West Brom relegated it did have the feel of a testimonial match for Tugay after eight seasons at Ewood Park.
He was given a standing ovation when he came off in the 85th minute to be replaced by Martin Olsson, in turn responding by waving to all corners of the ground as his name was chanted loud and long by a grateful home support.