Marcelo Bielsa questioned Mexico's approach after Darwin Nunez scored a hat-trick in Uruguay's comprehensive 4-0 friendly win over El Tri in Denver. (More Football News)
Uruguay warmed up for their Copa America campaign with their seventh win in 12 games under Bielsa (three draws, two defeats), thrashing a much-changed Mexico side.
With Mexico set to face Brazil in their final pre-tournament friendly on Saturday, head coach Jaime Lozano benched the likes of Santiago Gimenez and Alexis Vega and saw his team torn to shreds.
Uruguay raced into a 3-0 lead by half-time as Nunez netted twice and Facundo Pellistri converted Brian Rodriguez's cross, then the Liverpool man made it a treble by finishing into an empty net shortly after the interval.
After the win, former Leeds United boss Bielsa suggested Mexico took the game lightly, saying: "I think a team that is preparing should have taken today's game with maximum power, knowing that they have to play Brazil."
However, Bielsa expects far more from El Tri at the Copa America, where they have been drawn in Group B alongside Ecuador, Venezuela and Jamaica.
"It was a deceptive result, in the first half Mexico could have scored and it would have been different," he said.
"Don't lose sight of the fact that today there were many important players out of the team, too many.
"Keeping the stars they had on the field today and adding the players that came on, Mexico will be a very difficult opponent."
Uruguay begin their Copa America campaign against Panama on June 23, taking on Bolivia four days later and rounding off Group C against the host nation, the United States.