A goal in each half proved too much for the Colorado Rapids as they slipped to a 2-0 defeat to San Jose Earthquakes in the inaugural Las Vegas Pro Soccer Challenge Cup on Sunday night.

Chris Wondolowski opened the scoring for Dominic Kinnear's side just shy of the break, before JJ Koval doubled the advantage 16 minutes from time.

Pablo Mastroeni started with four new signings, two trialists and five regulars from 2014. Michael Harrington began at left back, ahead of Marc Burch. The defensive midfield roles were taken by Sam Cronin - formerly of San Jose - and Lucas Pittinari, with Marcelo Sarvas sitting behind lone striker Dominique Badji.

"I think it was a good exercise for the guys," said Pablo Mastroeni. "I think the first component of this game was to make sure we were competing, having not played in an organized game against a different opponent.

"The second part was the fitness element, and making sure that these guys get enough minutes in a game that has a higher pace than what we've been training at, and so I think we've achieved both those things."

Wondolowski had earlier volleyed just wide, but followed up his own rebound on 43 minutes to beat Irwin and edge the Quakes ahead. Irwin was replaced by trialist Quentin Westberg at the interval. Ten new players came in at the 63 minute mark, before Koval added a second for the Californian side following a Leandro Barrera corner.

Earlier, Rapids striker Dominique Badji fired just over, while David Bingham saved well in the Quakes' goal to keep the match scoreless, moments before Wondolowski struck.

"I think it was clear that this was our first real test of preseason," admitted Sam Cronin. "(We're) not super sharp yet, but mentality was good and spirit in the side was good - which is important."

The Rapids now head to Arizona and the Desert Diamond Cup in Tucson. Their first match of that tournament is on Wednesday, when they take on Sporting Kansas City, kick-off 5.30 p.m. MT. This match will be streamed live on ColoradoRapids.com.

COLORADO RAPIDS 0:2 SAN JOSE EARTHQUAKES

Preseason Exhibition – Cashman Field; Las Vegas, NV.

Scoring Summary:

SJ - Chris Wondolowski, 43'

SJ - JJ Koval, 74'

Rapids lineup: Clint Irwin (Quentin Westberg, 46'); Wes Knight (Francisco Flores, 63'), Shane O'Neill (Joe Greenspan, 63'), Jared Watts (Axel Sjoberg, 63'), Michael Harrington (Marc Burch, 63'); Sam Cronin (Andrew Ribeiro, 63'), Lucas Pittinari (Ben Newnam, 63'); Vicente Sánchez (Carlos Alvarez, 63'), Marcelo Sarvas (Oscar Montoya, 63'), Dillon Serna (Gabriel Torres, 63'); Dominique Badji (Caleb Calvert, 63').

Quakes lineup: David Bingham, Marvell Wynne (Brandon Barklage, 63'), Victor Bernardez (*Trialist, 63'), Ty Harden (Clarence Goodson, 63'), Jordan Stewart (Shaun Francis, 46'), JJ Koval (Pablo Pintos, 79'), Chris Wondolowski (Adam Jahn, 46'), Matias Perez Garcia (Mike Fucito, 63'), Sanna Nyassi (Leandro Barrera, 46'), Jean-Baptiste Pierazzi (Tommy Thompson, 63'), Shea Salinas (Cordell Cato, 63').

Disciplinary Summary:

SJ - Chris Wondolowski (caution, 28')

COL - Sam Cronin (caution, 38')

SJ - Ty Harden (caution, 47')