The 24-run win levelled the two-match series 1-1 and dashed Pakistan's hopes of replacing Sri Lanka as the number one team in the Twenty20 rankings.
Chandimal said his team showed great resolve in their comeback win after losing the first match, which was also in Dubai, by three wickets.
"We are over the moon. We keep our No. 1 rankings and it's a matter of great delight," said Chandimal after the match.
Openers Kusal Perera (59-ball 84) and Tillakaratne Dilshan (33-ball 48) set the platform for a big 211-3 total, putting up 100 by the 12th over.
Seekkuge Prasanna, playing his first Twenty20 hit an aggressive eight-ball 21 while the experienced Kumar Sangakkara gave the final touches with a rapid 21-ball 44.
"Kusal and Dilshan batted really well. After that Seekkuge and Sangakkara batted well at the end. You know he's a legend (Sangakkara)," said Chandimal, who admitted beating Pakistan was not easy.
"They played exceptionally well so we had to come back. They have some very good bowlers and we had a gameplan and we executed that in the middle and that's why we won the game."
Pakistan were on course for achieving the target at 83-3 but lost Sharjeel Khan (50), Umar Akmal, Umar Amin and Bilawal Bhatti (all three without scoring) in the space of seven balls and two runs.
Pakistan captain Mohammad Hafeez conceded losing four wickets in the middle was the turning point.
"We were going well but lost four wickets in the middle which really made the difference and the credit goes to Sri Lanka," said Hafeez, who also blamed bowlers.
"We leaked some runs as a bowling unit. We were thinking of chasing 160-170 on this track," said Hafeez.
Sohail Tanvir (41) and Saeed Ajmal (20) put on 63 for the ninth wicket -- the best for this wicket in all T20 cricket -- but the target proved beyond Pakistan's reach.
"As captain I am happy to see good performances from Sharjeel and Tanvir and we really achieved what we wanted to before the mega event," said Hafeez, referring to the World Twenty20 in Bangladesh in March-April next year.
"We had a plan and we wanted to inject some youngsters to check our combination for the mega event and we have achieved that," said Hafeez.
The two teams now play five one-day internationals with the first game in Sharjah on Wednesday.