The Mercer Island boys basketball team won its first in-league game Friday by beating a former rival from the 1980s and 1990s. The 62-49 victory against Juanita was energized by a 31-11 rebound advantage and a 13-0 run to start the second quarter. Peter Zajac led the Islanders with 17 points and Jon Poli put up 14 points and 10 rebounds to pace Mercer Island.