The two sides faced each other in the competition on Thursday, which sees past and present footballers go head-to-head in seven-a-side games with the aim of ultimately winning a $1 million prize, but the match ended abruptly.
The Irons team, featuring the likes of Frank Nouble and Anton Ferdinand, walked off the pitch after a racial slur was allegedly uttered by a Dallas player. Clips on social media showed Ferdinand's anger at the incident.
Dallas have since been suspended from the competition, after TST officials investigated the allegations and confirmed that they had violated the code of conduct set out at the beginning of the tournament.
They said in an official statement: “We have been in dialogue with leadership from both clubs and we are all aligned that the best path forward is Dallas United withdrawing from competition. All parties involved are unified in wanting to make a statement against racial insensitivity.”
The report claims that officials at TST heard a Dallas player using the n-word, with Nouble seemingly the target.
Nouble confronted the player immediately, and West Ham's squad then gathered at the side of the pitch before deciding to walk off.
Dallas claimed that they had pulled out of the competition themselves, but the statement from TST makes it clear they have been removed over the vile comment.
West Ham are due to play again on Friday, when they are scheduled to go up against a side named Culture by Mo Ali FC.