Messi then ensured there would be no way back for an Alaves side lackig cutting edge by classily volleying home his second of the afternoon from the edgeof the box.
City, needing three points to become champions of England for the seventh time, took the lead just before half-time through Raheem Sterling's close-range strike.
But Mount's withdrawal did not hamper Chelsea as they managed to finally edge the League One outfit 2-1 during the first half of extra-time, thanks to Marcos Alonso's goal.
Not for the first time in Liverpool's run of success under Klopp, it was a late goal that decided the match. "Late goals - we don't want to need them but they were necessary and important.
"In a time when manners are teetering on the edgeof extinction and anxiety is on the rise, it is increasingly important to spend time expressing gratitude.
Inter came out from the break firing and were rewarded for their hardwork when captain Martinez found space on the edgeof the box to bend a wonderful effort into the far corner.
Arsenal went behind shortly after half-time when their goalkeeper parried a cross to the edgeof the box, with James Milner guiding the ball into the back of the net.
A Nigerian man has taken to his twitter page to share photos of his damaged smartphone after it exploded without being plugged to electricity. The man said he was lucky he did not have it on his person at the time it happened.
Recall that last year's Headies award, Rema was able to edge out other artistes such as Zlatan, Joeboy, FireBoy, Victor AD and Lyta. Rema revealed that his busy schedule delayed pick up of the prize.
Antwerp took a first-half lead when Alhassan Yusuf swept home a shot from the edgeof the box, but Porto were level seconds after half-time through Evanilson's deflected strike.
Record signing Alexandre Lacazette doubled the lead on 27 minutes, bending a shot past Asmir Begovic from the edgeof the area. Welbeck than added a third just after half-time, scoring from a tight angle into Begovic's far corner.
Bu Deportivo fought back just after the hour mark when Joselu blasted into the top corner from the edgeof the box. Two minutes later, Depor were 2-1 up.
Willian and Ross Barkley scored in either half, as the Blues dumped Klopp's men out of the competition in the fifth round. It means Liverpool have now lost twice in a row for the first time this season.