Barnsley’s hopes of securing a club-record sixth successive away league win were thwarted by an in-form Leyton Orient side in a 1-1 draw at Brisbane Road.
Joe Pigott gave Orient a first-half lead from the penalty spot before a superb 20-yard strike by Herbie Kane levelled matters.
The visitors ended the match with 10 men following the dismissal of substitute Sam Cosgrove.
Orient nosed ahead in the 27th minute when referee Peter Wright ruled that a shot by Ruel Sotiriou had been handled by Jamie McCart in the penalty area.
After vehement protests from the Tykes players, Pigott stepped forward to calmly slot the ball home.
The Tykes should have levelled a minute into the second-half when Devante Cole picked out Max Watters at the far post with Sol Brynn stranded but the Barnsley forward stabbed the chance wide from five yards.
The visitors deservedly levelled, however, when Kane exchanged passes with Cole before drilling his shot into the roof of the net from 20 yards out.
Cosgrove was booked in the 89th minute for a foul and two minutes later was again shown the yellow card for dissent, resulting in his dismissal.