LONDON — Dele Alli bolstered his growing reputation by putting a stop to Chelsea’s 13-match winning streak, scoring two goals on headers on Wednesday to give Tottenham Hotspur a 2-0 home victory over the Blues, the Premier League leaders.

Defense has been the bedrock of Chelsea’s three-month hot streak, but Alli found space to score nearly identical goals, one in each half, after connecting with crosses from Christian Eriksen.

Alli, 20, who has now scored seven goals in four games, helped hand Chelsea its first loss since its last trip to north London, at Arsenal in September, and prevented the Blues from earning a league-record 14th successive win in a single season.

“This league is very tough,” Chelsea Manager Antonio Conte said. “Now it’s important to restart. After 13 wins in a row, it’s difficult to accept defeat.”