Spain ran its record to 3-0 at the 24-team tournament, which will produce two qualifiers for next year's London Olympics.
Toronto Raptors center Andrea Bargnani kept Italy in the game and in the tournament by scoring 36 points -- more than half his team's total -- in a 71-62 victory over Latvia. Bargnani had the highest-scoring game of the tournament so far. The only other Italian in double digits was Marco Belinelli of the New Orleans Hornets with 11.
Italy is 1-2 after three games in a tough Group B. Latvia, the youngest team in the event, is 0-3. Rihards Kuksiks led Latvia with 19 points.
Spain and Serbia are close to moving into the second round from their pools. The top three teams from each of the four groups advance.
"We're on the right path, but Lithuania and Turkey have more talent to give us more problems. We need to bring more energy and aggressiveness," Spain coach Sergio Scariolo said of his team's next Group A opponents.
Gasol's brother, Marc Gasol of the Memphis Grizzlies, added 18 points and 11 rebounds for Spain. Rudy Fernandez added 11 points for the Spaniards. Chicago Bulls forward Luol Deng led Britain with 17 points.
Serbia also won its third straight, using a big fourth quarter to rally past Israel 89-80. Serbia, which lost the final to Spain two years ago, awaits games against France and Germany. Israel dropped to 0-3.
Dusko Savanovic led Serbia with 24 points, including a key 3-pointer late in the game. Nenad Krstic, the former Oklahoma City Thunder and Boston Celtics center, added 18 points and Marko Keselj had 15.
"We didn't panic even when we were down by 12," Krstic said.
In Group A, Poland won its first game, beating winless Portugal 81-73 behind 18 points from Lukasz Koszarek.