Rotherham boss Paul Warne admitted the "schedule has caught up" with his side after their survival hopes were dealt a blow in a 1-0 defeat at Brentford.
Bryan Mbeumo scored the only goal of the game as the Bees made it two wins in a week and cemented their push for third spot.
The Millers' defeat puts the relegation fight back in Derby's hands, and Warne admitted: "The lads are exhausted, the schedule has caught up with us but we will keep going. On another day we might have nicked one at the end.
"It is absolutely exhausting and I don't know how the players players are doing it.
"We have a small squad and I'm exhausted myself. It feels like we've played a quarter of a season in a month and the sad thing is, if you are winning every week you feel a million dollars but when you lose you lick your wounds and they get deeper."
Warne bemoaned his side's lack of fortune, with a Covid outbreak, injuries and sending-offs stretching his squad to the limit.
But he stressed: "Unfortunately we are at the stage of the season where if it was the start we'd have been proud, but because we are desperate for points to stay in the Championship, it's bittersweet.
"It means a lot that people are rooting for us because people don't root for bad people. We've had a few injustices, but they are inspiring the lads to go on and that's what is keeping them going. I can't knock the lads' effort and I was very proud of them."
Warne said the run-in was "brutal" and added: "We've had games recently where we've been excellent and should have come away with points. I feel for my group and myself that we haven't got just rewards, but we will go to the end."
Head coach Thomas Frank feels his 10-game unbeaten Brentford side are starting to click as the play-offs move into view.
The Dane said: "It's important that we build momentum at this stage of the season and it was a hard-earned win.
"We are starting to see new relationships grow on the pitch at just the right time. We lost three key players in Josh Dasilva, Rico Henry and Henrik Dalsgaard so we've had to adjust and the run we are on shows we are doing that."
Frank hopes this will be the season where the Bees' consistency over the last two years will be rewarded, and he added: "Both years we have deserved more if you look at the statistics and numbers, but this is football and it is the small margins that decide things in the end.
"We don't want to be a great football team – we want to be incredibly lucky.
"This win wasn't easy. We had to fight and for the first 25 minutes we couldn't get control of the game, but one bit of class and brilliance from Sergi Canos and Bryan Mbeumo with the header changes the game."
Top scorer Ivan Toney hit the woodwork and fired wide as he chased his 30th goal of the campaign, but Frank added: "It's just a number, and we prefer to look at the performances and Ivan is a winner."
The Dane singled out German midfielder Vitaly Janelt, a close-season signing from Bochum, for special praise: "He is an unbelievable machine. He could lose a leg and still be running around with the same tempo.
"He's a top player, he has an aura about him and the best thing is he will only get better."