And ahead of this weekend’s assault on the FA Cup, he has demanded more from his players, fearful that a repeat performance will see a cup run come crashing down at the first hurdle.
The Robins had their wings clipped 2-1 by the Terrors at Colston Avenue, but Massey says there can be no complaints from inside his camp.
He said: “I was bitterly disappointed with our performance, it wasn’t acceptable.
“We had a penalty call against us that was a tad harsh but I’m not allowing anyone to hide behind that.
“I can be honest – as much as we deserved something against Worthing last week [a 1-0 defeat], we merited nothing on Monday.”
The defeat followed a 1-0 win on Saturday, where Ricardo Panton got the only goal at the Ryman League Division One South’s early whipping boys Walton Casuals.
On Monday, a late rally saw striker Kingsley Aikhionbare grab Carshalton’s first home goal of the season with a smart finish, but it was not enough to inspire a full comeback.
Massey said: “We didn’t work hard enough to win the ball back when we lost it and we gifted them a lot of chances.
“Issues like that, plus other things like individual fitness levels, they will all be worked on.”
Carshalton are on their travels in the FA Cup preliminary round this Saturday as they play Mole Valley SCR of the Combined Counties Premier League.
“They’ll be up for this so we’ll need to be on our game,” Massey said.
“We have had a fair start to our season and I do not want us to start going backwards.
“We’ll regroup and train hard because we want to progress in the competition.”