Bradford Bulls' shock win against Super League side Salford Red Devils in The Qualifiers is testament to James Lowes' coaching, says ex-player Jamie Peacock.
It was the first success by a Championship side against top-flight opposition in the Super 8s series.
And it was a marked change of form from their heavy 48-18 loss to Wakefield.
"They were some way off at Wakefield, but James Lowes showed his qualities as coach to turn that around," Peacock told the BBC Super League Show.
Victory lifted Bradford into third place in the middle tier, one of the three automatic promotion places for Super League 2016 with four games to play.
The final place will go to the team that wins the 'Million Pound Game' - a one-off showdown between the two teams that finish fourth and fifth after seven games.
"It's given real hope to the Championship sides to show the Super League sides can be beaten," said Peacock, who played for the Bulls between 1999 and 2005.
"The competition has been blown wide open, when it comes to who is going to finish fourth or fifth, there are plenty of questions after that game."
Hull KR captain Tyrone McCarthy, whose side still have a 100% record in this section, were handed a boost by the win ahead of their Challenge Cup final appearance on Saturday.
"That win was the shot in the arm The Qualifiers needed," McCarthy said.
"It's a bit of an upset this weekend and it helps Hull KR, it makes it a bit easier after we won this weekend."