Conte, who joined on a three-year contract last July and had been set a pre-season target of securing a top-four place and Champions League qualification.
He has surpassed the expectations of even owner Roman Abramovich, who offered his congratulations via technical director Michael Emenalo.
An improved contract offer is likely, especially as Inter Milan covet the former Juventus and Italy boss.
Conte pointed to September’s 3-0 loss at Arsenal, which prompted a change in formation to 3-4-3, as a pivotal moment.
“I found the strength to take the responsibility to change system, to find a new suit for these players,” he said.
“I think it was the key moment for us. Every single player found in this system the best for them.”