On Sunday, Christian Pulisic made a crucial contribution for Chelsea by scoring a last-minute winner over West Ham.
In the 76th minute of the Premier League match, the United States international came off the bench to replace Timo Werner.
In the end, the change was essential for the Blues, as he went on to score the game-winning goal for his team.
Until the last minutes of the game, the London sides appeared to be set for a 0-0 draw at Stamford Bridge.
Chelsea were handed a lift when Craig Dawson was sent out for a tackle on Lukaku in the 86th minute, resulting in a penalty kick for the home club.
Jorginho, though, missed the penalty kick, sending it straight into the arms of Lukasz Fabianski.
Pulisic stepped up to make the difference late in the game when a pass from Marcos Alonso found him in space and he was able to blast into the net.
With six games remaining, the result retains Chelsea in third position in the Premier League.
They lead fourth-placed Arsenal by five points, with Tottenham trailing by two.
Meanwhile, ahead of their match against Everton on Sunday, championship challengers Liverpool sit 11 points ahead of Thomas Tuchel's side.
Chelsea's next match is on Thursday against Manchester United.