Ben Sheaf struck with the last kick of the game to secure a winning end to pre-season for the Sky Blues.
Matty Godden had put City in front, after he was on the end of a corner into the box, diverting the ball past Sinsalo.
However, the hosts drew level when Vince Harper’s cross evaded everyone and found the back of the net, ten minutes from time.
Then, with the last kick of the game, Ben Sheaf went past one and then another, before finding the bottom corner to secure the win.
City also saw Luis Binks wear the Sky Blue shirt for the first time, as he made his maiden appearance in the second half.
City started brightly and a fine move which saw Kasey Palmer release Ellis Simms, ended with the striker teeing up Ben Sheaf on the edge of the area, but his effort curled over the bar.
The hosts first shot on target came just before the half-hour mark, as Pierce Sweeney was at the back post from a corner into the box, striking the ball straight into the hands of Brad Collins.
At the other end, Kasey Palmer’s ball into the box was met by the head of Bobby Thomas, but he could only find the side netting.
Moments later, another City attack, this time down the left, saw Simms pull the ball back for Godden, but he watched on as his shot was palmed away by Sinsalo.
HALF-TIME: Exeter City 0-0 Sky Blues
In the second half, Sam Nombe came the closest to breaking the deadlock six minutes in, heading narrowly wide from inside of the six yard box.
The Sky Blues found their best opportunity five minutes later with Josh Eccles picking out the head of Godden, but his diving effort was saved by Sinsalo.
Matty was getting closer to finding his first of pre-season, latching onto a through ball by substitute Gustavo Hamer, but his shot, which looked destined for goal was blocked on the line.
The birthday boy would get that goal he was looking for from the resulting corner, heading past Sinsola and giving City the lead.
Godden could have had another seconds after the restart, racing through on goal, only to be denied by the Exeter shot-stopper.
Matty was enjoying himself up top, finding pockets of space and creating chances and this time he was denied by the outstretched arm of the Grecians ‘keeper.
Ten minutes from time, Exeter found an equaliser through Vince Harper, as his cross from the left evaded everyone and fell into the back of the net.
Godden looked to fire the Sky Blues back in front with five minutes left on the clock, but his left-footed strike was well saved.
Then, with the last kick of the game, Sheaf latched onto Hamer's pass, took it past one and then another, before curling the ball into the bottom corner to make it a winning end to pre-season.
FULL-TIME: Exeter City 1-2 Sky Blues
Goals: Matty Godden, Ben Sheaf; Vince Harper
Sky Blues Xl: Brad Collins (GK); Bobby Thomas (62’ Binks), Kyle McFadzean (C) (81’ Howley), Joel Latibeaudiere; Jay Dasilva (76’ Bidwell), Josh Eccles (72’ Burroughs), Ben Sheaf, Tatsuhiro Sakamoto (62’ Hamer), Kasey Palmer (88' Obikwu); Matty Godden, Ellis Simms.
Subs: Simon Moore (GK), Jake Bidwell, Jack Burroughs, Luis Binks, Liam Kelly, Ryan Howley, Evan Eghosa, Justin Obikwu, Gustavo Hamer.