Leeds led at halftime through Raphinha, but was punished again for failing to take his chances and after Junior Firpo’s second-half own goal, Antonio dismissed the Hammers’ goal in the final minute.
The hosts’ inability to convert opportunities threatens to undermine their second season back at the top flight and they slipped into the bottom three.
Marcelo Bielsa’s team has equaled the club’s longest winless streak since the start of a league campaign, marked in 1935/36 and again in 1951/52.
West Ham started off full of confidence after their impressive start to the season and threatened to sweep Leeds aside early in the first half.
Injuries and Leeds suspension forced Bielsa to hand over to center midfielder Charlie Cresswell his Premier League debut and the Hammers, led by Antonio, rigorously scrutinized the 19-year-old’s play.
He said Benrahma fired an early shot and Antonio’s low-angle unit was deflected by the slightest of touches from Illan Meslier.
Meslier was forced to make an even better flight stop shortly after to avoid another effort from Benrahma.
But Leeds grew steadily in the game and Stuart Dallas’s curly shot was superbly knocked over the crossbar by West Ham goalkeeper Lukasz Fabianski.
Raphinha then served as a warning of his game-changing abilities by cutting in and shooting directly at Fabanski, but the Polish international had no chance with the Brazilian’s next effort.
After being hit by Mateusz Klich on the edge of the penalty area, Raphinha fired a low left-footed shot into the bottom corner to give Leeds a lead in the 19th minute.
Raphinha hit a post from an identical position in the 35th minute, but West Ham finished the first period strong.
Antonio simply couldn’t get to the center end of Benrahma’s far post and after a rare error from Kalvin Phillips, Meslier produced a brilliant block to deny Pablo Fornals on a heads up.
West Ham thought they had equalized early in the second half when Tomas Soucek turned the ball home from close range after a corner kick.
But Antonio’s elbow had clearly caught Meslier in the face as the goalkeeper jumped to catch the ball and after VAR intervention, referee Kevin Friend dismissed him and admonished the visiting striker.
Meslier parried Soucek’s shot and on the other end Klich rejected a golden opportunity to double the home team’s lead from inside the area when Raphinha set it up.
Leeds had to pay soon after, as the action continued to ebb and flow and the Hammers tied in the 67th minute, albeit in fortuitous circumstances when a Jarrod Bowen cross was deflected at Firpo.
Raphinha was retired and replaced by Tyler Roberts and Leeds failed his straight run at the counter.
Both teams were looking for the winner, but it was West Ham who seized their opportunity when Declan Rice selected Antonio with a good inside pass and the Hammers forward maintained his composure to shoot home a low shot.