United States coach Steve Kerr wants to see higher levels of intensity from his team as their Olympics campaign approaches.
Kerr was unhappy with the lacklustre displays from his side in their warm-ups against Germany and South Sudan.
Germany led 71-68 at the end of the third quarter before LeBron James conjured up 11 points in the final four minutes to give the USA a 92-88 win, while South Sudan were 20 seconds away from pulling off one of the biggest shocks in basketball history, before eventually falling to a 101-100 loss.
The USA face a dangerous Serbia side featuring reigning NBA MVP Nikola Jokic on Sunday, and Kerr is adamant that improvements are required if they are to win a fifth consecutive Olympic gold medal.
He said: "It's got to be 40 minutes of force and attention and focus, and we can't let teams outplay us effort and energy-wise like we did the other night against Germany, like we did against South Sudan.
“We have another level. I think we have another two levels that we can get to, but it's a collaboration, always.
"We can show them, 'Let's do this, let's do that. Let's learn personnel.'
"We got to know the shooters, know the non-shooters, all that stuff. So that's where we can help them. Where they can help themselves is just effort and energy play after play, after play. This is different."
Kerr is a four-time NBA champion as a coach, and was part of the triumphant Olympics team in Tokyo in 2021, but the Golden State Warriors boss knows the experience of the Games will only be enhanced if the USA were to come out on top again.
"This should be one of the great experiences of our lives. But the best way to make it an incredible experience is to win a gold medal," he said.
After facing Serbia, the USA will once again go up against South Sudan, this time in a competitive format, before ending the group stage with a match against Puerto Rico.