Goals from Emmitt Delfouneso, Marcel Henry-Francis, Reece Hales and Josh Hawker secured the win for Richard Beale’s side.
The Midland Alliance side replied in the second half through Tony Green, but that strike was not enough for the side managed by former Blues trainee Delton Francis.
Beale’s visitors showed their intentions early on with Jack Deaman testing Karl Hunter in the home goal in the first minute.
Possession and corners were in abundance for Blues in the early stages and their early pressure almost told in the 16th minute when Hales rattled the crossbar. After a winding run and precise through ball from Morgaro Gomis, Hales checked on to his right-foot and crashed an effort off the woodwork.
That sparked Star in to life and, three minutes later, their captain Davion Hamilton was allowed space to turn before firing just wide from distance with Nick Townsend at full stretch.
However, the deadlock was broken soon afterwards. In the 25th minute, a whipped corner by Deaman from the left-hand side was met at the near post by his defensive partner Delfouneso and his firm header flew past Hunter.
Blues doubled their advantage just two minutes later and it was again from a set-piece. Ben Gordon’s right-wing free-kick was met by Deaman at the near post and his flick-on fell to the feet of Henry-Francis; who could not miss from six yards out.
Hales then spurned a good chance and Henry-Francis had an effort cleared just in front of the goal line as Blues looked to put the game out of sight before the interval.
The break rescued the hosts and they came out with more vigour in the second half, with Deaman lucky to stay on the field four minutes in. The centre-back was initially beaten by the pace of Ricardo Reid, whom he eventually brought down. Fortunately, he was not adjudged to be the last man and was given just a yellow card.
From the resultant free-kick, Hamilton curled a right-footed effort that clipped the frame of Townsend’s goal.
The impressive start to the half continued for Star and they clawed a goal back in the 55th minute through Green. The ball was worked well into the Blues box, before Hamilton’s scuffed effort found Green alone at the back post and he made no mistake with his simple tap-in.
Eddy Gnahore almost replied instantly for the visitors, latching on to a loose back pass, but he was quickly closed down by Hunter. But the goal that effectively killed the tie came in the 76th minute through Hales.
Substitute Liam Truslove found space in front of the defence and fed a delicious through ball to Hales who rounded Hunter and slotted in with great composure.
Two minutes later, the victory was sealed. The impressive Truslove was again involved and his vicious strike from the right-hand side of the area was parried out by Hunter, but fell to the feet of captain Josh Hawker to tap home.
Reid spurned a late chance for a Star consolation before Truslove could have capped an excellent cameo display, but his 20-yard strike whistled just past the post as Blues progressed to the next round.
Blues U21’s: Townsend; Higgins, Gordon, Delfouneso, Deaman; Gray (Truslove, 72), Gnahore (Ntambwe, 79), Gomis, Hawker; Hales, Henry-Francis (Fry, 72)
Unused subs: Preston, Ebanks.
Continental Star (numerical order): Hunter, Wright, Davis, Hunt, O’Garra, Green, Hazell, Hamilton, Reid, Garvey, Benjamin.
Unused subs: Holgate, Ellis, Robinson, Tomlinson, Mutambire.