Tampines coach Jurgen Raab was left feeling "angry" after the Singapore giants' winless streak extended to three matches, with their defence again cruelly exposed.
The Stags were knocked out of the Singapore League Cup on Tuesday night after falling to a 3-1 defeat at the hands of Geylang International at Jurong West Stadium.
That followed a 5-1 reverse in the competition at the hands of Brunei DPMM three days earlier, and a frustrating 1-1 draw in the S.League on June 29.
Although Raab rested some key players for the League Cup games, the German rued his side's inability to convert chances, and tendency to make defensive blunders.
"There was a big difference between performance and score," Raab said. "We had better chances in first half [against Geylang] and we should have led 2-0.
"Same mistakes, like against DPMM, we are too open at the back. When we equalised, we spent too long celebrating, we didn't concentrate and let in another. Players must learn, if we play offense, organisation is important. "
Tampines will now be playing for no more than pride in their final Group B game on Friday when they face Balestier Khalsa, who have also been eliminated after consecutive defeats.
By blooding some Prime League players in the League Cup, Raab hopes it will pay off in the long run in the S.League.
"With the performance it's really a good development [for the younger players]," he said. "I'm angry for the players to leave with this score, but they must learn.
"We must improve quality, but it's a process for me to learn attacking and defensive behaviour. We can only look forward when we learn, now we try to make a better result. Against Balestier, we want good performance and good result."
Geylang International and Brunei DPMM will face off for top spot in Group B on Friday night.