The Dutch Grand Prix was derailed by two rain showers, the latter of which prompted a red flag due to severe aquaplaning into Turn 1, which caused a crash for Alfa Romeo's Zhou Guanyu.
At the start of the lap 62 downpour Verstappen wasn't entirely convinced about coming in for intermediates yet, with his race engineer Gianpiero Lambiase urging him that "it would be a good time to pit" as the track conditions worsened rapidly.
Afterwards team principal Horner revealed the call to err on the safe side and bring in his driver came from him.
"We were a bit unsure of what was going to happen with the weather; was it a few spots, was it going to blow through?, Horner said.
"And in the end, I was shouting at GP: 'Get him in!'"
Horner says his team nailing the strategy, on a day when the likes of Mercedes, McLaren and Williams didn't, was part luck and part risk management.
"I think it's a combination of the two," he added. "There were so many things that could go wrong.
"We saw calls being made early on where cars dropped out of contention, into contention.
Source: Autosport