The Timberwolves led early in the third quarter but failed to keep up with the Blazers, who produced a strong response to seal a 115-104 triumph.
"The second half we just ran out of gas," Adelman told reporters. "I noticed it.
"We made runs at them, we caught them in the third quarter, but they kept having one more run."
Minnesota face a trip to play the Chicago Bulls on Monday night.