"I have lost a good friend and a wonderful cricketer who served the country so well," Imran said in his condolence message.
The cricketer-turned-politician said Qadir's death was a shock to him.
Imran played an instrumental role in turning Qadir into a household name as it was under his captaincy that the leg-spinner flourished to secure many Test and one-day victories for Pakistan, including a 9 for 56 in one Test against the West Indies at Faisalabad in 1986.
Chief of Army Staff (COAS) Gen Qamar Javed Bajwa also expressed "heartfelt grief" on the death of the cricket legend.
"The COAS expresses heartfelt grief on the demise of cricket legend Abdul Qadir," DG Inter-Services Public Relations (ISPR) Maj Gen Abdul Ghafoor tweeted.
"Pakistan has lost a great sportsman and a human being. May Allah bless his soul and give strength to the bereaved family to bear this irreparable loss, Ameen," he quoted the COAS as saying.
President Arif Alvi also issued a condolence message lamenting that Pakistan had lost a great sportsman and human being.
Pakistan's current skipper Sarfaraz Ahmed and other cricketers too issued condolence messages and paid tributes to Qadir.
"Absolutely shocking news to hear the sad passing of legend Abdul Qadir sahib. May Allah grant him the highest rank in jannah and his family the patience to bear the loss," tweeted Sarfaraz.
Former bowler Shoaib Akhtar tweeted a video message over the demise of Qadir noting that the death of the legendary leg-spinner had come as a big shock to him.
"Just got this sad news. The revival of leg-spin in cricket is completely credited to him. He inspired a generation of bowlers to take up leg-spin."
Legendary cricketer Wasim Akram, in his condolence message, said that
Qadir was called the magician for many reasons but "when he looked at me in the eyes and told me that I was going to play for Pakistan for the next 20 years, I believed him."
"A magician, absolutely. A leg spinner and a trailblazer of his time. You will be missed Abdul Qadir but never forgotten," he wrote.
Former captains, Javed Miandad, Rashid Latif, Moin Khan and others including Basit Ali, Muhammad Yousuf, Iqbal Qasim and Danish Kaneria also offered their condolences and said Pakistan cricket had lost a great figure and performer.
"No one can realise what Qadir was. He was a true magician and the only bowler I have known who would get batsmen out by announcing beforehand he would get him with this delivery," Miandad recalled.
Qadir's son, Sulaman, told the media that his father never complained of any heart ailment and his death from a cardiac arrest had left the family devastated.
"...he was at home having dinner when he suffered the heart attack and although we rushed him to hospital, he expired on the way," he said.
Qadir became an icon for keeping the art of wrist spin alive in the '70s and '80s with his bouncy and unique run-up and flamboyant personality.
Qadir played 67 Tests and 104 ODIs to pick up a total of 368 wickets in his international career.
All four of his sons -- Rehman, Imran, Sulaman and Usman -- have played first-class cricket in Pakistan. His youngest son Usman, also a leg-spinner, appeared in the Big Bash T20 league last season....