Marc Roberts' powerful header provided a deserved lead at the break.
And Blues looked a fair bet to see things through until an equaliser in the 90th minute.
Blues then endured disappointment in a penalty shoot-out, losing 4-3 to the Portuguese second division side.
Blues began in 3-4-2-1, the formation they have been honing in pre-season training.
Steve Seddon and Maxime Colin doubled as wing-backs when Blues dropped into a defensive shape.
Isaac Vassell was up front, with Kerim Mrabti and Odin Bailey either side, slightly withdrawn.
On a hard pitch and warm evening, it was very much getting back into the swing of things in this opening friendly after weeks of hard graft before either side really made headway.
A big diagonal pass from right to left just eluded Wes Harding's jump and although Femi got in, his heavy touch allowed Lee Camp to dive at his feet in the area.
Blues were eager and aggressive, and opened the scoring in the 36th minute from a corner.
It was earned when Bailey checked back onto his left foot just outside the area and bashed a shot that was blocked behind.
From Mrabti's raking, flat kick to the far post Roberts rose and powered down and in a header that was too hot for a squirming 'keeper.
At the break Blues made six substitutions, with Harlee Dean taking the captain's armband from David Davis.
Harding, Roberts and Dean constituted the back three.
Again, the half was keenly-contested and unfortunately for Blues their lead was let slip in the 90th minute.
In the first real move of intent, Blues got in on the left through a burst by Seddon, who was snuffed out.
And then Blues almost extended their lead from a corner, sent over by the energetic Charlie Lakin.
Lukas Jutkiewicz headed the ball back into the mix, Seddon half-hooked it at goal and Joe Redmond was about to apply the finishing touch at the front post, but had the ball nicked off his head.
David Stockdale, who came on for Camp at the break, had little to do bar claim an inswinging free-kick, at which he was fouled in the air.
But he had the disappointment of picking the ball out of the net right at the death when a punt forward was taken down well by Sami, to the left of the area, who promptly stuck it away with power via the outside of his boot before Stockdale could get set.
Blues had to contend with a share of the spoils and in the subsequent penalty shoot-out - they are scheduled after the end of every match to help decide tournament placings - Stockdale made one stop, but unfortunately unsuccessful attempts by Jude Bellingham (saved) and Jutkiewicz (over the crossbar) meant a 4-3 loss, despite spot-kicks hitting their mark by Craig Gardner, Lakin and Dean.
Blues first-half (3-4-2-1): Camp, Harding, Roberts, Pedersen, Colin, Seddon, Gary Gardner, Davis, Mrabti, Bailey, Vassell.
Blues second-half (3-4-2-1): Stockdale, Harding, Roberts (Redmond 70), Dean, Dacres-Cogley, Seddon, Craig Gardner, Lakin, Mrabti (Bellingham 59), Bailey, Jutkiewicz.