"It's an awesome thing for all our guys and girls at Shell V-Power Racing, Ford Performance, to be the first to win the Triple Crown is really cool," McLaughlin said. "It's a big team effort. We're missing our boy Richard [Harris, data engineer] at home in the UK, our thoughts are with him.
"I've got a great car, great team, the pitstops were unreal. I had a good battle with Fabs at the start.
"I'm just lucky. I'm 26, just living the dream driving race cars and I'm lucky I drive a fast one."
McLaughlin held off Coulthard through Turn 1 to keep the lead, as Reynolds snuck ahead of the latter and into second in the opening exchanges.
The championship leader waltzed away at the front to lead by 7.6s when he and Reynolds pitted together on lap 19 of the 70.
While McLaughlin emerged in front, Reynolds was behind four drivers to have made earlier stops, led by Cameron Waters.
McLaughlin's buffer during the second stint grew to more than 13s over Waters, who had Coulthard and Reynolds for company before the final round of stops.
Reynolds was back into second after the fuel strategies had played out, ahead of Coulthard and Waters.
He was 10s behind McLaughlin, whose second stop on lap 43 featured a slight delay to merge in behind wildcard runner Jack Smith in the lane.
But that was the extent of his troubles, McLaughlin taking his 12th win of the season and 37th of his career.
Reynolds could not repeat his 2018 Sunday victory at Hidden Valley but cemented third in the championship with his third podium in the last four races.
"We've still got a bit to catch these cars around me," Reynolds said. "It was a really, really good job by the boys, we were the fastest in pitlane, they just told me. We did everything we could, just didn't get there."
Coulthard had to settle for third place, albeit within a second of Reynolds.
