For a number of days, it has been reported that Tomasson's spell in charge at Ewood Park was coming to an end, a result of the club's poor form in the Championship.
Although Rovers narrowly missed out on a Championship playoff spot in 2022-23, a prolonged disappointing run of results has left the club down in 18th position in the standings.
While Blackburn have reached the FA Cup fifth round, just five points have been accumulated from their last 11 fixtures in the second tier.
As a result, Blackburn and Tomasson have agreed to go their separate ways by mutual consent, the Dane posting 40 wins and 36 defeats from his 90 matches in charge.
At a time when Tomasson is allegedly in contention for the Sweden job, Blackburn have moved swiftly to bring in Eustace, who has been out of work since his controversial exit from Birmingham City.
Eustace had Blues in a playoff spot during the early stages of the campaign before the club's owners opted for a change in manager, a decision that has not paid off.
From Eustace's perspective, though, his reputation is firmly intact and the 44-year-old has penned a two-and-a-half-year contract.
Speaking to the club's official website, Eustace said: «I am delighted to be the new Head Coach of such a fantastic football club as Blackburn Rovers, which has such a proud history and tradition within the game.
»I am excited for this new challenge in my career and can't wait to get started. I am looking forward to being at Ewood Park tomorrow and meeting the supporters, who can play a big part for us between now and the end of the season.
«I will give my all to ensure theRead on sportsmole.co.uk