One week after blowing a huge early lead at home against Belgacom Liege, Cajasol slipped to a 78-70 defeat at Ventspils.
Unlike their loss to Liege, however, this time the Spanish club trailed by 15 points on three occasions in the first quarter and once early in the second.
Martínez's team managed to claw the deficit back to just one point in the fourth quarter and twice had opportunities to go in front but missed shots.
Latvians BK Ventspils won for the first time to leave both sides with 1-2 records in Group A.
The pivotal sequence of plays in the game occurred in the last two minutes.
Pedro Rivero del Caz hit a three-pointer to pull Cajasol to within just one at 71-70 with 2:06 to play.
Ventspils' Akselis Vairogs, coming out of a timeout, was off target with a jumper and Cajasol rebounded.
Niklas Caner Medley went to the other end and quickly put up an attempt from beyond the arc and missed and Ventspils rebounded.
Medley came up with a steal, however, and Cajasol's Dusko Savanovic had a good look inside but missed a lay-up and again Ventspils grabbed the rebound.
This time, Vairogs went to the other end and nailed a jump shot for a 73-70 Ventspils lead 44 seconds from the end.
Needing a three to tie the game, Rivero del Caz had the ball stolen by Tyrone Brazelton.
Martins Skirmants made a jumper shortly after for a 75-70 advantage. Fouled in the act of shooting, he converted the three-point play to make it 76-70.
Brazelton added two more free throws for the eight-point margin of victory.
One of the star performers in the game for Ventspils was Juris Umbrasko. He buried five of his six attempts from behind the arc and scored 17 points.
Brazelton also finished with 17 while Ronalds Zakis had 12 rebounds to go with his 10 points.
For Cajasol, Rivero del Caz scored 16 points.
Ventspils out-rebounded Cajasol 41-33.
Each team hit 18 of 20 attempts at the free throw line.
Pedro Martinez, coach Cajasol:
"We started this game badly, but we defended strongly. We had a bad shooting percentage, [lost the] rebounds and didn't create fast breaks. This is why it was difficult to win. We have to improve our performance."
Pedro Rivero del Caz, player Cajasol:
"We started the game badly and during the game we didn't improve our performance. We knew that we would be having problems with Ventspils, if we didn't play good defense."
Agris Galvanovskis, coach Ventspils:
"We fulfilled our plan. Of course we made some mistakes, but the team played well. The only surprise from Cajasol was Rivero del Caz, who scored many baskets, however we neutralized all the other players. Many players from our team are able to score many points, however it is hard to play against taller players like Cajasol is, but somehow we managed to do it. I am happy about this game, because we had lost three times in a row before tonight. I think this is because in the last 10 days our team had been preparing hard for this game. This victory will definitely motivate our players. Brazelton was playing today and therefore our team played better."
Juris Umbraško, player Ventspils:
"The coach told us to stick to the plan. Of course we made some mistakes, but as a whole we did what we had to do."