After an auspicious start in Belgium, the Hammers found themselves a goal down with less than five minutes on the clock as Joseph Paintsil burst past Issa Diop and fired a shot past Alphonse Areola.
The east London outfit have been incredibly bright this season, but needed the early goal to spark them into life as Declan Rice began to get control in midfield.
It was a difficult pitch to play on amid slippery conditions, but the Irons nearly fashioned an equaliser when Michail Antonio found himself unmarked in the box and tried to force a pass through to Declan Rice, only to see the ball deflected and then cleared off the line.
Moyes has not reached this particular milestone for no reason and, after starting the second half brightly, he made a triple substitution on hour mark which brought about the equaliser.
Manuel Lanzini fed the returning Vladimir Coufal down the right hand side and the Czech Republic international cut the ball back to the impressive Said Benhrama to stroke home.
Unperturbed by his omission from the England squad, Jarrod Bowen proved a real handful upfront with his pace and movement and nearly created a winner, but Craig Dawson could only nod his cross wide of the post.
The game was seemingly sealed with nine minutes of time to play when Benrahma showed his magisterial class as he burst into the box on the left hand side, drove past three defenders and fired a low shot past Maarten Vandevoordt.
The Algeria international had seemingly written his name into the headlines, only for substitute Tomas Soucek to deflect a cross from Junya Ito into his own net past the despairing Areola.
The point means West Ham are still top of their Europa League group on ten points and can seal qualification this evening if there is a winner in the Rapid Wien vs Dinamo Zagreb game, with a group winner being decided on matchday five.