German striker Klose was given his marching orders for a second bookable offence in the 37th minute, leaving his team all at sea and allowing Serbia to snatch the only goal of the match moments later.
Defender Arne Friedrich said the referee was too eager to brandish cards.
"With almost every foul he pulled a yellow card," he said.
"There are few players who didn't get one."
Klose will be ruled out for Germany's next match against Ghana on Wednesday, which will decide if the three-times champions can advance to the next round.
"We will miss (Klose) with his experience and his strong headers ... we have to find a way to make up for that as a team," said midfielder Thomas Muller. Germany coach Low said the second yellow card was "very harsh" and doubted it was necessary.
"(Klose) just tried to kick the ball away and then was unlucky to hit the opponents leg," he said.
In total, seven other yellow cards were given out, including four for Serbian players.
"There were a couple of tackles where I felt the yellow cards were justified but there were many yellow cards given for tackles that weren't malicious at all and could have been avoided," Low said.
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