With former MLS Defender of the Year Jamison Olave sidelined for his third straight game, the pair filled in ably to help stem the team's ignominious losing streak.
Before he was released in May, Mansally played primarily forward and midfielder in six seasons with the New England Revolution. When he played with the Gambian national team, however, he shifted to left back experience that showed in the 23-year-old's 90th MLS match.
In the 60th minute, Mansally overran a short pass back from forward Fabian Espindola, falling to the ground as he tried to stop himself.
The miscue turned into a chance to show off his athleticism, as he chased down forward Mauro Rosales just outside the box. In the 79th minute, he slid into a timely stop of a cross attempt.
"For the past four or five days, Kenny looked like he was ready for a start," Kreis said. "I think he showed it tonight."
The caveat is that the performances came against a struggling offense that hasn't won an MLS game in nine tries. For Salt Lake fans, it didn't matter. When Mansally was finally subbed out in the 79th minute, the sellout crowd of 20,363 saw him off with some of the loudest cheers of the night.
Watson-Siriboe, whom Real acquired from the Chicago Fire last week for a 2014 fourth-round draft pick, was more of an unknown quantity. He hadn't even had a chance to go through a full training session in Salt Lake.
"With Kwame, we rolled the dice a little bit," Kreis said. "He came in clean."
The 25-year-old said that leap of faith, along with guidance from captain Kyle Beckerman and defender Nat Borchers, helped him into his first MLS game since 2010.
"Most thing I've been missing in my career is confidence," Watson-Siriboe said. "Here, they've really given me the confidence to go out and play."