London (AFP) - Liverpool reached the English League Cup last 16 after an extraordinary third round tie saw them beat second-tier Middlesbrough 14-13 in a penalty shoot-out on Tuesday, while Southampton knocked Arsenal out of the competition.Both goalkeepers scored in a shoot-out at Anfield where all 22 players still on the field took spot-kicks before Middlesbrough's Albert Adomah fired wide to ensure eight-times League Cup winners Liverpool's victory.Earlier, 17-year-old striker Jordan Rossiter marked his Liverpool debut with a 10th-minute goal before Adam Reach equalised for Middlesbrough just after the hour.All square after 90 minutes, it substitute Suso had done enough to give the hosts victory with a 109th-minute goal that made it 2-1.But with virtually the last kick of extra-time, Boro's Patrick Bamford scored from the penalty spot to make it 2-2 after being brought down by Kolo Toure in the box.In the shoot-out that followed, Bamford saw his effort saved early on before Liverpool's Raheem Sterling also failed to score.The match then moved into sudden-death and the tie wasn't settled until Adomah missed with the 30th penalty of a remarkable shoot-out.For record eight-times League Cup winners Liverpool, this was a badly-needed victory after their 3-1 league loss to West Ham and set them up for this weekend's Merseyside derby with Everton."It was very important to get a result and the players are very happy in the changing room," said Liverpool manager Brendan Rodgers."We're in the hat and that's all we want.