كتب : Omar AbdelAziz
Goals from Yuichiro Nagai, Brazilian forward Washington and an own goal from Hadi Aghily sealed the victory for Urawa, before Mahmoud Karimi grabbed a late consolation for Sepahan.
The Japanese side, who beat Sepahan in last month's AFC Champions League final, will now meet European champions AC Milan in Yokohama on Thursday.
The other semi-final clash will see Copa Libertadores champions Boca Juniors of Argentina entertain African Champions Etoile Sahel on Wednesday.