The Brazilian – who has been on the substitutes' bench for his side's last two Premier League games – scored one and made two others as Antonio Conte's men bounced back in style from their surprise weekend defeat to West Ham.
His first contribution was to play in Tiemoue Bakayoko for the opener after 23 minutes before getting on the end of Marcos Alonso's cross just before half-time to score just his second league goal of the season.
He turned provider again after 50 minutes to tee up Pedro for Chelsea's third and cap an impressive individual display.
Huddersfield, who had won three of their previous four home games, offered little in the way of attacking threat until Laurent Depoitre nodded in a 92nd-minute header and David Wagner now needs to pick his side up for a difficult trip to Watford on Saturday.
Chelsea, meanwhile, go level on points with Manchester United in second and will be full of confidence ahead of the weekend visit of Southampton - a game that Willian will surely be guaranteed of a starting berth in.
Chelsea, who started with Eden Hazard up front in the absence of Alvaro Morata, dominated possession in the early stages and saw a fifth-minute Pedro effort ruled out for offside.
Despite controlling the game, it took until midway through the first half for them to carve out a clear opening, which duly resulted in the opening goal.
Jonas Lossl slipped while attempting a long ball downfield, which was clinically punished by the visitors.
Victor Moses headed the skewed clearance into Hazard, whose backheel fed Willian on the edge of the penalty area. The Brazilian then spotted the marauding Bakayoko and played it into the Frenchman's path for him to clip an immaculate finish over the red-faced Terriers goalkeeper.
N'Golo Kante then thrashed over from the edge of the area and Bakayoko headed wide before Willian grabbed a deserved second two minutes before the interval.
Alonso collected Cesar Azpilicueta's raking cross-field pass and whipped in a teasing cross to the back post, which was coolly headed past Lossl by the 29-year-old.
Any faint hopes Wagner's side had of clawing their way back into the game were vanquished five minutes after the restart as Willian teed up Pedro to whip a fine finish into the top corner from 15 yards.
Lossl then saved well from Hazard to deny Chelsea a fourth before Tom Ince, who has still yet to score for Town, saw his effort clip Thibaut Courtois and dribble away to safety.
Pedro came close to a second late on when he whipped wide. The final say was Huddersfield's, however, as Depoitre rose highest to head home fellow substitute Florent Hadergjonaj's teasing cross with what was the last meaningful action of the match.
Key Opta stats:
- Chelsea's win at the John Smith's Stadium means the Blues have won at 50 different stadiums in the Premier League; only Liverpool have won at more stadiums in the competition (53).
- Huddersfield have lost five of their last six Premier League games (W1), conceding two or more in all five of those losses.
- Chelsea have scored 10 headed goals in the Premier League this season (a league high) – they only scored eight in the entirety of last season.
- At 17 years and 89 days old, Ethan Ampadu is the second youngest Chelsea player to make an appearance in the Premier League after Jody Morris (17 years 43 days).