That was the verdict of boss Grant McCann after his side’s second of three big home games in the space of nine days.
Rovers followed up Saturday’s 3-1 victory over play-off rivals Peterborough United with an accomplished 3-0 win over Southend United on Tuesday night.
McCann named an unchanged side against the Shrimpers, choosing not to rotate at all.
Doncaster’s impressive display makes it is less likely that the Northern Irishman will change a winning team for this weekend’s sold-out fifth round tie at the Keepmoat Stadium.
But McCann is not concerned in the slightest about his team running out of gas against the Eagles.
“They’ve got loads in the tank,” said McCann. “They’re a fit group, a robust group.
“This started from pre-season, making them more robust.
“There’s no second day recoveries at our club. You don’t get a Sunday and a Monday off.
“You train Monday morning and you work hard.
“You train Tuesday and you work hard.
“That’s the way we live our life.
Yes we give them time when they need to recover.
“But when we’re in, we work hard.
“And I think we’re reaping the rewards of that now.
“The new physio I’ve brought in – you don’t want to be in there [in the physio room],” he added.
“Because he works you hard as well.
“There’s no rest in the physio department.
“So we’re delighted with where we are at the moment.
“There’s a long way to go in the league but now we can switch our focus to the FA Cup.”
Palace are set to discover on Friday whether star man Wilfried Zaha will be available to face Rovers.
They have appealed against an additional one-match ban handed to the Ivory Coast forward following his sending off at Southampton on January 30.