The striker was a substitute for the eighth straight game as Albion beat Newcastle 1-0 as Pulis said pre-game he had let himself down and was lucky to be on the bench.
He also hinted at problems with Berahino behind the scenes although it is understood there has been no specific flashpoint with the 22-year-old.
He threatened to strike after two deadline day bids from Tottenham were rejected and has scored just three goals since the summer transfer saga.
And, after Darren Fletcher's winning header, Pulis insisted while Berahino will not be fined his demeanour needs to get better.
"Sometimes supporters don't realise and understand exactly what goes on behind the scenes," he said.
"I always want the team to be a team, the supporters, the players, the management side, the directors, everyone together.
"Sometimes Saido does things that break away from that. He's been told, but he's been fine as you've seen today his reaction coming on was absolutely fantastic.
"He worked socks off and he's fine - no problems. At times you have to make him understand it's about the group and about the team.
"It's more a reminder it's about the group. You've got to look and understand Saido's had almost five months where he's not prepared himself or got himself ready and prepared to play in the team.
"He's a terrific player and he's got great ability and that great knack, even today coming on, of getting in great positions."
Victor Anichebe was given his first start since May ahead of Berahino and Pulis reserved praise for the former Everton striker.
"He's a top player. When Victor turns up he's a top player," he added.
"He's shown that today, he was a handful for them and they just couldn't handle him."