The German cut an agitated figure following Tuesday’s game with rock-bottom Argyle as his side had to settle for a point for the third game in their last four League One outings at Oakwell.
The Reds head coach was particularly critical of his side’s loss of concentration and focus after going ahead early on, before allowing the Devonians to dictate for much of the remainder of the first half and deservedly level.
Stendel has demanded that his side learn lessons ahead of Saturday’s game at high-flying Peterborough United.
He said: “The players need to learn fast that we need to be 100 per cent. It was our fault that we were not aggressive or defending 100 per cent after the first goal.
“That was not what we have showed in the past and I was very disappointed.
“For 30 minutes in the first half, we were very bad and I hope the players understand what they want at the end of the season.
“We can win every game, but we need a 100 per cent attitude in every game. Our next game against Peterborough is a very difficult game against a very good opponent.
“We must switch the attitude to 100 per cent to start 90 minutes or 95. The referee’s whistle is when he ends the game, not when we are 1-0 in front.
“All the players were concentrated and focussed against Fleetwood. We did not play the best football, but we worked against the ball and opponent and were very aggressive. We showed the same as the opponent and then we had more quality to win the game in the end.
“That is what we need in every game – whether it is against the team in last place or the first in the table.”
Stendel admits that he has no issue with the disgruntlement of fans following his side’s draw – and sympathised with their sense of frustration.
He added: “In all the games, we have had very good support from our fans.
“A lot of people come to the away games and show good support and the fans came to the home game on Tuesday hoping that we play a good game against Plymouth.
“I can understand that they were frustrated with the performance in the first half after going home.”