Reece James's free-kick in the 64th minute looked like it would be enough for the Blues at Bank of America Stadium, where weather caused a late delay, only for Angel Di Maria's stoppage-time penalty to force extra-time.

Nevertheless, Gianluca Prestianni's red card handed the initiative to Enzo Maresca's side, for whom Christopher Nkunku, Pedro Neto and Kiernan Dewsbury-Hall were all subsequently on target.

After a cagey start to the second period, James broke the deadlock with a moment of brilliance. The Blues captain snuck the ball in at Anatoliy Trubin's near post from a free-kick on the left wing, with the goalkeeper expecting a cross.

It looked like Chelsea would see out a narrow win, but play was suspended for two hours in the 86th minute due to adverse weather conditions.

When play finally resumed, Benfica equalised in the fifth minute of stoppage time, with Di Maria converting from the penalty spot after Malo Gusto was penalised for handball following a VAR review.

Yet, a second yellow card for substitute Prestianni within two minutes of the restart allowed Chelsea to regain control of the contest, and Nkunku bundled them back in front after 108 minutes.

The Blues then hit their opponents on the counter twice in the space of four minutes, with Neto and Dewsbury-Hall putting the tie beyond Benfica and setting up a quarter-final date with Palmeiras, who beat compatriots Botafogo 1-0 after extra-time earlier on Saturday.