Ronan Hale scored twice as Birmingham City hit back to beat Middlesbrough 3-1 in Group A at Bishop Auckland.
Matheus Caliman put Premier League 2 Division 2 leaders Boro ahead from close range in the 25th minute.
But Hale turned the match in Birmingham's favour with two goals from inside the penalty area in the 67th and 87th minutes.
Corey O'Keeffe scored City's third deep into stoppage time.
Derby County and Nottingham Forest are the other teams in the group and all four sides are now level on three points with two matches played, with Boro top on goals scored.
See: Middlesbrough report | Birmingham report
Next fixtures
Middlesbrough: 20 Nov v West Brom (A) PL2
Birmingham: 1 Dec v Nottingham Forest (H) PL Cup
