Middlebrough beat Chelsea 1-0 in the first leg of their Carabao Cup semifinal on Tuesday.
Hayden Hackney’s goal in the first half ensured the hosts have a slim advantage in the tie.
The 21-year-old finished off an Isaiah Jones pass in the 37th minute at the Riverside Stadium.
Middlesbrough then defended superbly in the second half.
Chelsea only had themselves to blame though as they dominated possession but squandered a host of chances — the biggest culprit being Cole Palmer who failed to hit the target twice in the opening half with the goal gaping.
Boro, who won the trophy in 2004, had chances on the counter-attack to increase their lead but will head to London believing they can reach Wembley.
Chelsea’s players were booed by some of their own fans at the final whistle but will have the chance to make amends in the second leg on January 23.
Liverpool host Fulham in the first leg of the other semi-final on Wednesday.