Two matches in a day
Earlier in the day, the third seeds defeated second seeded Finnish-Croatian pair of Henri Kontinen/ Franko Skugor 7-5, 6-2 to reach the final of the World ATP Tour 250 series tournament in Qatar's capital city.
Most of the matches were rescheduled due to an unexpected downpour in the Middle East country.
It's nice when you get that success immediately," Bopanna told ATP website.
"I'm really happy that I got this opportunity to come to Doha to play for the very first time. I've always played in India. When Wes was available, especially after such a successful 2019, it was a nice opportunity for me to play with him. It's good to start off the year with a title," Bopanna added.
"Last year, I won in Brisbane and three years ago I won in the second week in Sydney," said Koolhof.
"I'm always starting off the season well, so I think it's time for holidays again," Koolhof added.
The victory improves Bopanna and Koolhof's impressive individual records at the start of ATP World Tour seasons.
This is third time in four years that both players have claimed titles in the opening weeks of the season, having previously accomplished the feat in 2017 and 2019.