Young U's make Senior Cup progress.
It was a slow start to the game, with neither team able to penetrate the opposition defence or test the keeper.
However, they couldn't find an equaliser and the U's progressed through to the semi-final, when they'll host Concord Rangers.
Thurrock didn't lay down and die though, goals from subs Hazelwood and Wall reduced the arrears.
Bonne and Ladapo gave the U's a two goal lead at the break, with Harrison making it 3-0 just before the hour mark.
They beat Thurrock 3-2, with goals from Macauley Bonne, Freddie Ladapo and Callum Harrison.
The U's have made it through in the Essex Senior Cup.
The first real attack came from the visitors, with Warner getting in a good position wide on the left, but his low cross was taken well by Mark Cousins.
At the other end, Macauley Bonne couldn’t find the target with his header, after Callum Harrison’s cross was flicked on by a Thurrock defender at the near post.
Cousins had to be on his toes halfway through the first period, diving low to save an angled drive from dangerman Warner.
Chances were becoming more frequent now and Sammie Szmodics had a shot blocked before Tosin Olufemi’s rebound went straight into the keeper’s arms.
On twenty five minutes, the U’s took the lead, as Macauley Bonne latched onto a Dion Sembie-Ferris ball and slid his shot past the advancing former U’s keeper Andy Walker.
On the half hour mark, Jordan Sanderson had to go off with a foot injury, to be replaced by Marley Andrews.
Cousins kept the U’s lead intact, making a great double save in the thirty eighth minute.
That proved vital, as three minutes later, Freddie Ladapo doubled the U’s lead.
Bonne picked up a ball inside his own half, broke at pace and timed his pass to perfection, allowing Ladapo to steady himself with a touch before shooting low past the keeper.
Bonne had a late shot saved and Olufemi’s rebound was blocked, before the referee blew for half time.
The second half started with the U’s getting forward again, the first chance falling to Harrison after good work from Olufemi and Ladapo.
That effort was wayward and Ladapo’s effort then went straight at the keeper, before the visitors hit their first effort of the half over the bar.
A scare for the U’s came in the fifty fifth minute, when Spence hit the post after good work from Stimson.
As in the first half, a decent chance missed for Thurrock was quickly followed by a goal for the U’s.
Callum Harrison collected the ball just inside the Thurrock half, danced his way past a number of challenges and struck a shot from just outside the edge of the box.
Keeper Walker got a hand to it but could only touch it into the top corner and the U’s looked to have secured a place in the semi-final.
The visitors had other ideas though and a triple substitution helped get them back into the game.
One of the those subs, Loui Hazelwood, got a goal back a few minutes after entering the fray, beating Cousins with a shot from twenty five yards out.
Cousins then had to get down sharply at his near post to save, with the low effort coming in from the dangerous winger, Bradley Warner.
With seven minutes to go, Thurrock made it interesting with a second goal.
The visitors were allowed too much space down the right and when the cross came over, sub Ross Wall climbed highest to head home into the far corner.
It could have made for an uncomfortable finish for the young U’s side but they didn’t falter in the final stages and saw out the remaining time.
The semi-final will take place against Concord Rangers at the Weston Homes Community Stadium.