Chelsea midfielder Willian believes healthy competition for places has been one of the driving forces behind the Premier League leaders' assault on the title this season.

Chelsea have a 10-point cushion over second-placed Tottenham Hotspur with 12 games remaining.

Willian also feels the strength of the squad means manager Antonio Conte can rely on his bench to make an impact.

"Once we have a chance to come in (to the team), we have to try to do our best. It shows how together the whole squad is, not only 11 players," the Brazilian told British media.

"It's good to have 15 players or more that fight for positions, but in a good way, to try to help the team.

"And when we make a substitution in the game we are coming on and trying to do our best, for the team, and to help Chelsea win."

Despite scoring five goals in 22 league games, Willian has not started in the last three with Conte opting to use in-form Pedro in Chelsea's front line.

Chelsea travel to London rivals West Ham United, who are ninth, on Monday.