Wales captain Craig Bellamy hit out at the travelling supporters after John Toshack's side scraped a 2-1 victory away to 10-man San Marino.
First-half goals from Robert Earnshaw and Joe Ledley put Wales in control, but Andy Selva pulled one back with a superb free-kick before Nicola Albani was dismissed in the closing stages.
The Welsh fans made their feelings known after San Marino pulled a goal back, but Bellamy claimed to have been upset by earlier chants.
"I've played for Wales for a number of years and that's one of the worst atmospheres I've been in," Bellamy told BBC2 Wales.
"Some of the chanting early on was vicious.
"I'm proud to play for my country but this is the most difficult night I've been involved in."
Bellamy also refused to answer questions about manager Toshack's criticism of his "pampered" side in the wake of the defeat in Cyprus.
Goalscorer Ledley felt that Wales were poor in the second half but put part of the blame on the referee.
"I think we did well in the first half but were a bit slow in the second half and gave the ball away too many times," he said.
"I don't think the ref helped us as well. He gave a free-kick away on the edge of our box which wasn't one and they scored a goal."