Forward Kejoun Benjamin grabbed his first goal of the tournament with a header to give Rush an early 1-0 lead, but CESA rallied to win on a pair of second-half goals by Dylan Wolfinger.
Arslaval Conquerants, the lone Canadian entry in the boys Showcase competitions, improved to 2-0 with a 2-0 win over the Alpharetta Ambush Red.
Baltimore Bays Chelsea moved into Wednesday's championship thanks to its 1-0 win over GSA Phoenix Red.
BOYS U-17 SHOWCASE
Dallas Texans 1 Chicago Fire Juniors Red 0
Santa Clara Sporting 1 Weston FC 2
Elite FC Gladiators 2 Penn Fusion SA Coppa 0
Westside United FC 0 Solar SC 1
CESA Premier 2 Florida Rush Nike 1
Foothill FC MLVA Raptors 1 Sockers FC Chicago 2
Hicksville American SC Strikers 3 Tulsa SC Red 1
Blast FC Red 0 Concorde Fire 2
Alpharetta Ambush Red 0 Conquerants Laval 2
Team Ohio SC COSA 3 Andromeda 2
Campton United SC 0 Navy Florida Kickers 1
GSA Phoenix Red 0 Baltimore Bays Chelsea 1