India, on Thursday, beat arch-rivals Pakistan 2-1 to lift the junior Asia Cup trophy in Salalah, Oman.
According to sources, Aikman was not just unhappy with his salary not being credited, but also with "undue interference" from the other Pakistani coaches.
The Indian men's team will take on Malaysia and Poland on Sunday, while the women's team will face Switzerland and South Africa.
Angad Bir Singh (13th minute) and Araijeet Singh Hundal (20th) scored for India, while Pakistan managed to pull one back through Abdul Basharat (37th).
Manzoor Hussain, popularly known as Manzoor Junior, was a part of the Pakistan team that won bronze and gold in the 1976 and 1984 Olympics, respectively.
Both India and Pakistan finished on four points each in Pool A but the defending champions qualified for the Super 4s on better goal difference.
Aikman, who had joined the national team last year, took to social media to announce he had officially resigned as head coach.
Pakistan failed to qualify for World Cup as India replaced them at the number 2 spot in Pool A of Asia Cup Hockey 2022 with 16-0 win over Indonesia.
India have drawn against Pakistan but lost against Japan in Asia Cup hockey 2022 group games. Watch Indonesia vs India live.
Ken Nagayoshi, Kosei Kawabe, Ryomi Ooka and Koji Yamasaki scored for Japan while Pawan Rajbhar and Uttam Singh found the target for the Indians.
Pakistan lead Pool A with four points from two games in Asia Cup hockey 2022. Pakistan play Japan in their last pool encounter on May 26.
India's Asia Cup Hockey title defence started with an error-filled opener against Pakistan on Monday. The archrivals settled for a 1-1 draw in Jakarta.
India squandered their lead in the 59th minute to see the match against Pakistan ending 1-1. Get highlights of IND vs PAK Asia Cup hockey match in Jakarta.
Check match and telecast details of Asia Cup Hockey 2022, India vs Pakistan, Pool A clash - live streaming, squads, timing.
Birendra Lakra, who came out of retirement after Tokyo Olympics, will lead India in the Asia Cup hockey 2022 in Jakarta, Indonesia.
India will face Pakistan in their Asia Cup hockey 2022 Pool A opener on Monday in Jakarta, Indonesia. The tournament is a qualifier for 2023 Hockey World Cup.
Three-time champions, India will eye a record-equalling fourth Men's Hockey Asia Cup title. Check complete telecast and tournament details.
