After making his Premier League debut in Chelsea's humiliating 4-0 defeat to Bournemouth on Wednesday, Higuain enjoyed a rather more fruitful outing against the seemingly doomed Terriers in his Stamford Bridge bow.
Higuain opened his Chelsea account 16 minutes in, finishing after being released by N'Golo Kante, and Hazard made it 2-0 from the spot just before the interval.
Hazard got his second in the 66th minute when rounding goalkeeper Jonas Lossl, and Higuain followed suit a few moments later – his thumping effort deflecting off Terence Kongolo on its way in, and David Luiz wrapped things up.
It remains to be seen whether Higuain proves to be more of a success at the club than the likes of Alvaro Morata and Olivier Giroud, but Sarri is certainly optimistic about the striker combining with Hazard.
When asked if Higuain is the outlet Chelsea have been after, Sarri told reporters: "I don't know. I know very well that, when he arrived, he wasn't at the top of his physical condition.
"Now he is improving. I'm really very happy because, apart from the goals, my feeling is he's really suitable to play very close to Eden.
Double trouble! pic.twitter.com/4LJpIbtvjV— Chelsea FC (@ChelseaFC) February 2, 2019
"I think that, on the pitch, they are really very suitable to play one close to the other. For us, this is very useful for Higuain because he will be able to score a lot of goals, but also for Eden."
Although Chelsea were able to put their Bournemouth embarrassment aside, Sarri could not guarantee the Blues will not suffer a similarly worrisome result again.
"I'm not sure, but I hope [the Bournemouth loss was a one-time thing]," he said. "As I said before, we need to improve the mentality, we have to arrive at every match with the same level of determination and motivation, and we don't need to lose a match to have the right motivation.
"So, we need to improve. We'll try, of course, to improve. We need to understand that, in the future, we should not have to lose a game to add motivation."
It was a second successive defeat since taking over at Huddersfield for Jan Siewert, but the German is not panicking, adamant there were good signs from his team.
Asked if he was able to take any positives from the loss, Siewert said: "Everything. We were the ones who had the first chance, we were willing to play forward.
"We feel we created some good moments, but we have to be much more aggressive and willing to score. Sometimes we missed the moment of a shot or a pass. This is training work."