Goals from Charlie Webster, Harvey Vale andJude Soonsup-Bell ensured the Blues ran awaywith a deserved victory on Tuesday afternoon.
Webster struck excellently into the top cornerafter a cross on the right-hand side afterSoonsup-Bell saw a shot blocked to level thescores.
It was soon 2-1 after the ever-lively Soonsup-Bell was brought down inside the Zenit box andthe referee awarded a penalty.
Vale went straight down the middle from theresulting spot-kick, with the goalkeeper goingdown to his right.
Soonsup-Bell then got the goal he deserved aftera fine low cross from Vale found the Chelseanumber nine, who made no mistake with anassured finish from close-range.
Overall, it was a deserved victory for the youngBlues, despite a mixed first-half, with the hostsproving to be clinical in front of goal in thesecond period, which simply proved too much forZenit.