Derby County have announced the departure of head coach Paul Clement following just eight months in the job.
Clement has been sacked from his post despite the Rams being fifth in the Championship table, five points off first and second-placed sides Hull City and Middlesbrough.
The 44-year-old was handed his first managerial job at Derby in June 2015 after spending coaching spells at Chelsea, Paris Saint-Germain and Real Madrid.
Derby have gone seven games without a win in the league and chairman Mel Morris has claimed that Clement's dismissal occurred because the club have not made "enough progress" under his leadership.
"We are grateful for the contribution Paul has made to the football club but the time is right to make a change," Morris told the club's official website. "When Paul joined us last year we worked with him to develop a plan for the club which we asked him to embrace.
"It was clear in this plan, which was briefed to supporters, players, sponsors and all our stakeholders last summer that promotion this season was not the primary target. The priorities were building on the Derby way and style of football enjoyed in the past two seasons - adding depth and strength to our playing squad; and, developing and improving player and team performance.
"Sadly, on these measurements, we have not made enough progress and that is why we have decided to part company with Paul. I firmly believe that we have one of the very best first-team squads in this league. Our players are highly talented professionals who are more than capable of winning games at this level and beyond.
"I want to record our thanks to Paul for his efforts in leading the team through the first 30 games of this season and in achieving a top six position at this point. We wish him every success in his future career."
"We are in the fortunate position to have somebody as capable as Darren at our football club and he will be leading the coaching staff with immediate effect," said Rush.
"Our focus is to get the team back on track, delivering the style of football and performance we know they are capable of. I know our fans will give Darren, the coaching staff and the team their full support."
Derby will face MK Dons on Saturday.