Lehtera had four goals and two assists in three games last week as the Blues moved into top spot in the Central Division.
Montreal goaltender Carey Price was named second star while Nashville centre Filip Forsberg took third-star honours.
Lehtera began the week on Tuesday with a hat trick in a 6-1 win over Buffalo. He recorded two assists in a 4-3 victory over Nashville on Thursday and closed the week Saturday with a goal in a 4-1 win over Washington.
Lehtera's point streak now stands at seven games (five goals, six assists).
Price posted a 3-0-0 record, 1.33 goals-against average, .950 save percentage and one shutout as the Canadiens won all four games for the week to move into first place in the overall NHL standings.
Forsberg had two goals and three assists in three games for the Predators.