The visitors took the lead in the first-half, before a James Tavernier penalty early in the second period drew Rangers level. However, a double from Joao Carvalho saw the Greek side win at Ibrox.
Robby McCrorie started in goal with a back four of James Tavernier, Ben Davies, John Souttar and Borna Barisic.
Nico Raskin, Kieran Dowell and Todd Cantwell were in midfield with a front three of Sam Lammers, Cyriel Dessers and Abdallah Sima.
It was Rangers who got the action underway at Ibrox as Cyriel Dessers kicked-off in his first start for the club.
Beale’s side started with intent and came close to finding a breakthrough goal early in this friendly. Kieran Dowell fired the ball into the box from the right with the clearance falling for Nico Raskin. On the volley, the midfielder struck an impressive shot at goal from distance but Paschalakis was able to gather.
Olympiacos came close as Masouras cut the ball back to Iborra on the edge of the area but he dragged his shot wide as he looked to find the net.
In a set-piece opportunity for the visitors, a free-kick was swung into the area by captain Konstantinos Fortounis in search of Rodinei Marcelo De Alemida but his header was saved comfortably by Robby McCrorie.
At the other end, Lammers tested Alexandros Paschalakis after lovely footwork from the Dutch forward saw him beyond two Olympiacos players before getting a strike away but the goalkeeper matched the shot as he managed to push it wide.
Just before half-time, it was the Greek side who took the lead at Ibrox. A ball from Joaquin Ruiz was deflected into the path of Konstantinos Fortounis who struck the ball and with the help of a deflection inside the box it bounced beyond McCrorie into the Rangers goal.
Beale made two changes at half-time as Jon McLaughlin was introduced between the sticks for Robby McCrorie, while Johnly Yfeko replaced Ben Davies at centre-back.
Five minutes into the half, Rangers were awarded a penalty as referee Steven MacLean pointed to the spot after Todd Cantwell was taken down by the goalkeeper in the box having been played through by Sam Lammers inside the box.
From the spot, captain James Tavernier drew Rangers level with a well-executed right-footed penalty.
With 56 minutes on the clock, Olympiacos were back in front at Ibrox. Youssef El Arabi’s shot from close range was turned away from goal by Johnly Yfeko but Joao Carvalho followed-up to score for the visitors.
Shortly after, Sima linked-up well with Dowell with the former directing a low shot on target but it was tipped wide by the goalkeeper.
There were three changes for Rangers with just over half an hour of the game to play as Ridvan, John Lundstram and Fashion Jr were introduced in place of Borna Barisic, Kieran Dowell and Cyriel Dessers.
Lammers was again denied by the goalkeeper as he pulled off a fine save to deny his low drilled effort, before Masouras headed wide a chance for the Greek side shortly after.
There was a second goal of the evening for Joao Carvalho as he found the back of the net with a low shot after getting on the end of a ball from Rodinei Alemida.
For the final 20 minutes, Rabbi Matondo and Ianis Hagi came on in place of Abdallah Sima and Nico Raskin.
Matondo had a good chance to get on the scoresheet as he was picked out in the box by John Souttar. He turned well to be able to get a shot away at goal but it was held comfortably by the Olympiacos goalkeeper.
Youngsters Bailey Rice and Zak Lovelace were introduced for the last 10 minutes, with Sam Lammers and Todd Cantwell making way at Ibrox.
Rangers will play their final pre-season match away to Hoffenheim on Saturday afternoon.
RANGERS: McCrorie (McLaughlin, 46), Tavernier, Davies (Yfeko, 46,) Souttar, Barisic (Ridvan, 61), Dowell (Lundstram, 61), Raskin (Hagi, 74), Cantwell (Rice, 81), Sima (Matondo, 74), Lammers (Lovelace, 81), Dessers (Fashion Jr, 61).
Subs: Butland.
Olympiacos: Paschalakis, Retsos, Camara, Fortounis, Iborra, El Arabi, Ruiz, Masouras, Carvalho, De Alemida, Ntoi.
Subs: Tzolakis, Papadoudis, Ramos, Bouchalakis, Androutsos, Vrousai, Ba, Jaume, A. Camara.
Referee: Steven MacLean