Chelsea suffered a shock defeat away at Middlesbrough in the first leg of the Carabao Cup semi-final.
Hayden Hackney ghosted into the box to tap in Isaiah Jones's cross to give Michael Carrick's team a 1-0 lead going into a second leg at Stamford Bridge.
False nine Cole Palmer was the most guilty of wasting chances as Mauricio Pochettino opted to play without a striker.
Armando Broja and Mykhailo Mudryk came on in the second half, but Middlesbrough secured an important lead ahead of a second installment in two weeks' time.
Nizaar Kinsella was at the Riverside Stadium to witness the action.
Djordje Petrovic - 6
The goalkeeper couldn't do much about Hackney's close-range effort but was rarely tested otherwise.
Malo Gusto - 5
He was less effective than he has been in recent weeks and took some heavy challenges down the right.
Axel Disasi - 6
Disasi dominated his box against the physical Josh Coburn but had one dreadful 55th-minute shot.
Thiago Silva - 5
His lack of pace was an issue as the left-sided centre-back - offered no protection to Colwill.
Levi Colwill - 4
Colwill was constantly exposed at left-back as nearly all Middlesbrough attacks came down his side, including the moment that created the goal. He also missed a huge chance early on.
Moises Caicedo - 6
The British transfer record midfielder was the one bright spark in the first half, creating a big chance and almost scoring with a good edge-of-the-box shot.
Enzo Fernandez - 5
Fernandez wasn’t as decisive with the ball as you’d expect given such long spells of possession.
Cole Palmer - 5
Palmer missed a host of first half opportunities, including an open goal and a one-on-one.
Conor Gallagher - 5
Gallagher wasn't his usual effective self in an advanced position, but had a decent shot fly wide midway through the second half.
Noni Madueke - 5
Madueke linked well with Palmer and created chances but his finishing was poor and he was substituted early.
Raheem Sterling - 5
The experienced winger was largely anonymous throughout but somehow stayed on the pitch for the full 90 minutes.
Substitutes
Mykhailo Mudryk - 7
The 23-year-old winger produced some good crosses and was the only creator in the second half.
Armando Broja - 5
Broja struggled to make an impact from the bench as Chelsea struggled to create while under pressure.
Alfie Gilchrist - N/A
Unused subs: Bergstrom, Bettinelli, Williams, Golding, Washington