Mauricio Pochettino's side travel to Stamford Bridge on Monday night and have not given hope up of overhauling Leicester in the final three games of the season.
Chelsea, meanwhile, have little left to play for and are languishing in ninth place, nine points adrift of the top six.
But Willian is adamant an opportunity to derail Tottenham's title bid - as well as personal pride - is serving as motivation among Guus Hiddink's squad.
"We don't want Spurs to win the League. Of course we want to win against them," Willian told Sky Sports.
"It will be a difficult game, a massive game.
"And I repeat, we have to win for our pride, for Chelsea, not because Spurs are fighting to win the League," he added.
"Of course the fans of Chelsea don't want them to win the title and we have to - not only this game but until the end - we have to win every game."
Spurs boast the best attack in the division ahead of their short trip across the capital but Chelsea could be boosted by the return of both Gary Cahill and John Terry.
Tottenham have not won in west London for 26 years but their efforts on Bank Holiday Monday could yet be in vain if Leicester are victorious at Old Trafford on Sunday afternoon.
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