Chelsea's 1-0 defeat at Manchester City on Sunday means the Blues cannot finish in the top half of the Premier League this season.
City manager Pep Guardiola picked a much-changed side for Sunday's game at the Etihad after the Sky Blues' third successive title was confirmed on Saturday following Arsenal's 1-0 defeat at Nottingham Forest.
But the champions came out on top thanks to an early goal scored by Julian Alvarez on an afternoon of celebration for the Manchester club and their fans.
For Chelsea, it was the 15th Premier League defeat in a miserable season which has seen three different managers in charge of the west London club.
Thomas Tuchel was dismissed early in the season and replaced by Graham Potter in September, only for the former Brighton boss to lose his job in April.
Blues legend is now in charge as interim, with the Stamford Bridge side set to appoint a new manager in the summer.
With two games left, Chelsea are in 12th place and sit nine points behind local rivals Fulham in 10th. With Brentford above the Cottagers in ninth, the Blues are only the third-best of the three west London sides in the top-flight this term.
Lampard's side have two tough games ahead, too, with a trip to Manchester United on Wednesday followed by a home game against Newcastle next Sunday.