Rashford capped a comfortable win in the 89th minute when United broke and Ibrahimovic teed up the England youngster to fire a fizzing shot into the bottom-left corner from an acute angle.
"After Liverpool and Manchester City's victories, if we didn't win today it's nearly mathematically impossible (to finish fourth)".
United took their foot off the gas with the match all but won and Thursday's Europa League quarter-final at Anderlecht looming large, with Defoe leading the hosts' attempts to reduce the deficit. "We have no players, we need him to be available for the next match".
About a month ago, Manchester United Manager Jose Mourinho said the roster he now has, inherited from predecessor Louis van Gaal, would be quite different if the decisions made in the recent past were up to him.
Mourinho revealed in the pre match buildup that first-choice keeper David De Gea picked up an injury which forced him to make the switch.
And Mourinho argues: "What is clear is, by playing in the Premier League, in Europe, in the cups, he is having an fantastic experience, after the hurricane that he was last season, when he came in, this year is giving him a hell of an experience".
He has to change his football brain, ' Mourinho said. It's good for Sergio Romero to play before Brussels. We had a couple of situations but no more than that and we were playing quite compact and solid.
Chicharito is one of the three players that Mourinho mentioned back around St. Patrick's Day. "De Gea will probably be fit for Chelsea - yes, if he's in good condition".
The picture is bleaker for their former boss Moyes and Sunderland who have now gone seven top-flight matches without scoring - the joint second worst sequence in Premier League history.
Sunderland's afternoon would worsen before half-time, though, when Larsson was dismissed for a somewhat reckless challenge on Herrera, though he was perhaps unfortunate not to receive only a yellow given how little contact there was with the United man.
"With the Community Shield and EFL Cup in the pocket, the Europa League is the only competition we can win". We gave away a poor goal and I thought we needed to get a lot closer.
"I told them in the second half we had to go to kill the game".
"I have sympathy with every manager that is fighting hard to reach their objectives", he said. "But I didn't think it was a good decision".