Former players Friday blamed Pakistan's failure to make the most of their chances for their 1-0 defeat to Sri Lanka, which ended the side's two-year unbeaten run in Test series.
The third and final Test ended in a draw on Thursday, handing Sri Lanka their first series win in three years after their 209-run victory in the first game in Galle.
It is Pakistan's first Test series defeat since the notorious England tour in 2010, which they lost 3-1 and was marred by the spot-fixing scandal at Lord's.
The result also ends Misbah-ul Haq's unbeaten run in seven series as captain, a spell that included a 3-0 whitewash of world number one Test team England in the United Arab Emirates earlier this year.
Former captain Aamer Sohail said missed opportunities cost Pakistan dearly.
"Pakistan had opportunities in all three Tests but they let them slip away and that cost them the series," Sohail told AFP.
"Pakistan didn't read the pitches correctly in all three Tests of this series and that's why they didn't select the right combination of 11 players."
Former chair of selectors Sohail said Misbah was short of ideas for how to use his bowlers in Sri Lankan conditions.
Former batsman Basit Ali blamed off-spinner Saeed Ajmal, who was the tourists' top wicket-taker in the series with 15, for being ineffective.
"In my opinion Ajmal did not do as much as he should have done," said Ali. "Ajmal didn't bowl as well as he could have in the final Test.
"That's why I believe (coach Dav) Whatmore needs a bowling coach for his assistance. Pakistan didn't give new ball to Mohammad Sami in the final Test which was surprising for me because Sami is very fast and could have done well."
Ali praised Asad Shafiq, who scored his second Test ton in the last match, as an outstanding batsman for the future.
Former paceman Jalaluddin praised left-arm fast bowler Junaid Khan as the find of the series.
"Junaid really impressed in this series," he said of the paceman, who finished with 14 wickets in three Tests. "He showed a lot of progress and can go places in the future."