Spurs dominated the opening 70 minutes in North London but West Ham scored with their first shot on goal as Obiang found the top corner of Hugo Lloris's goal from 30 yards.
However, six minutes from time, Son also netted from distance to earn Spurs a deserved share of the spoils after having 31 shots on goal in comparison to just three for the Hammers.
Find out how all of the action unfolded in North London courtesy of Sports Mole's minute-by-minute updates below.
TOTTENHAM HOTSPUR SUBSTITUTES: Vorm, Trippier, Wanyama, Dembele, Winks, Lamela, Llorente
WEST HAM UNITED SUBSTITUTES: Hart, Makasi, Haksabanovic, Quina, Ayew, Carroll, Martinez
TOTTENHAM HOTSPUR XI: Lloris; Aurier, Sanchez, Vertonghen, Davies; Dier, Sissoko, Eriksen, Alli, Son; Kane
WEST HAM UNITED XI: Adrian; Reid, Rice, Ogbonna; Zabaleta, Kouyate, Noble, Obiang, Masuaku; Lanzini; Hernandez
If you would like to read our on-the-whistle match report, you can do so by clicking here. Goodbye for now.