Until Friday's announcement Warner Bros was straddling the high-definition fence by releasing movies in both formats, the only major Hollywood studio to do so.
"We remain firm in the belief that HD-DVD is the format best suited to the wants and needs of consumers," said Akio Ozaka, head of consumer products at Toshiba in the US.
Ozaka added that he was "especially surprised" at Warner Bros' decision considering the "significant momentum that HD-DVD has gained in the US market and other regions".
Despite Toshiba's defiant declaration, analysts are less certain of the fate of the HD-DVD format.
"It is interesting that Ozaka said he was 'surprised'. I think that's an understatement. 'Devastated' would probably be more accurate," said Peter King, an analyst at consulting firm Strategy Analytics.
"Toshiba has an uphill battle. It is hard to see what they can do. Maybe focus on the PC market as a format, but they have a major struggle and that was very clear today."
Although King stopped short of declaring Blu-ray's victory a certainty, he did add that a conclusion to the war would be good for the consumer electronics industry as a whole.
"Everyone could get behind one format and start promoting. The message will be simple and clear: prices will come down and it is a good thing for the industry," he said.
An inadvertent side effect of the Warner Bros announcement could be a major upset to the game console war between Microsoft and Sony.
Microsoft is rumoured to be announcing a new version of its Xbox 360 with an integrated HD-DVD drive to compete directly with Sony's PlayStation 3 which includes a Blu-ray drive.
This power shift may see Redmond rethinking its plans, however.