Manchester City crushed League One Notts County 5-0 in a fourth-round replay and Bolton Wanderers won 1-0 at Fulham in an all Premier League fifth-round tie.
The result in east London left Orient fans celebrating as if they had won the game and dreaming of finishing the job in the replay at Arsenal's Emirates Stadium to earn a quarter-final meeting with Manchester United at Old Trafford.
But Tehoue's goal means they will replay at the Emirates on March 2 with the money raised set to provide a financial lifeline for the League One club, 53 places below Arsenal in the ladder.
Orient chairman Barry Hearn promised his squad a trip to Las Vegas if they avoided defeat and laughed afterwards that his manager Russell Slade had out-thought Arsenal's astute boss Arsene Wenger by leaving it late to bring on Tehoue.
"The best thing for us was that it was 1-0 with only a couple of minutes to play because Arsene is not going to put on any of his main line from the bench, because he is trying to nick it, get away with a 1-0 win," Hearn said.
"If we'd have equalised in the 70th minute, on would have come (Cesc) Fabregas and all the rest of them, and we'd have been in trouble. "But Arsene got a little bit complacent and our Frenchman put the boot in," he joked.
"He scored a great goal but we had the right attitude, we were focused and they took advantage of one of our few mistakes," Wenger said.
"It was difficult for us to create more chances and credit to them for they defended well."
Bolton maintained their hopes of a first FA Cup final appearance since they last won the competition in 1958 by ending Fulham's interest at Craven Cottage.
