Manchester United narrowly avoided one of the most embarrassing cup exits in their history, only beating third-tier struggler Rochdale in a penalty shootout after conceding a goal to a 16-year-old school kid in normal time.

On a night when top-flight teams West Ham, Bournemouth and Sheffield United were eliminated by lower-division opposition in the third round of the English League Cup, United had a major let-off at Old Trafford despite fielding a lineup containing Paul Pogba and US$60-million offseason signing Aaron Wan-Bissaka.

Rochdale, who are languishing in 17th place in the 24-team League One, had a shot cleared off the line before going behind to a goal by 17-year-old United striker Mason Greenwood. He wasn’t even the youngest player to score in the match, with Luke Matheson — playing the 14th game of his professional career at a ground close to his high school — equalizing in the 76th minute to take the game to penalties.

United converted all their spot kicks in the shootout and won it 5-3. The reward: A fourth-round trip to Chelsea, who had a much easier time in dispatching fourth-tier Grimsby 7-1 at home.

The performance and result highlighted United’s lack of strength in depth this season, though Greenwood continues to be a bright spark. He scored for a second straight match at Old Trafford, having grabbed the winner against Astana in the Europa League last week.

Elsewhere, third-tier Oxford rested six of their regular players but still thrashed West Ham 4-0 in an embarrassing result for the team who beat Man United in the Premier League at the weekend. All of Oxford’s goals came in the second half at Kassam Stadium.

Third-tier Burton Albion beat Bournemouth 2-0 in a match featuring three floodlight failures that led to 28 minutes of second-half stoppage time being played, and Sheffield United lost 1-0 at home to third-tier Sunderland.

Brighton were the fourth Premier League team to lose Wednesday, beaten 3-1 at home to fellow top-flight side Aston Villa.

Teenager Ki-Jana Hoever scored his first senior goal for Liverpool in a 2-0 win away to MK Dons. It was Liverpool’s first win in the competition in almost three years. Liverpool will host Arsenal in the last 16. The holders Manchester City have been drawn at home to Southampton. (AFP)