Paul Pogba opened the scoring in first half stoppage time only for James McArthur to equalize for Palace midway through the second half. It appeared that Jose Mourinho's men would be unable to hold onto a lead once again only for Ibrahimovic to find the breakthrough.
What did we learn from the match?
1) Paul Pogba is only going to keep getting better
Pogba had a mixed game, looking excellent one moment before giving the ball away the next. He played Wayne Rooney in on goal with a gorgeous chipped ball midway through the first half and went close to opening the scoring with a terrific volley five minutes before the break. He then got himself in the right position to open the scoring in a first half which he had dominated.
However, in the second half he was frequently caught in possession and gave the ball away cheaply. As Palace got themselves back into the game, he drifted in and out and grew visibly frustrated. That frustration didn't stop him from crafting Ibrahimovic's winner.
Pogba didn't stop going forward, and showed his strength to shrug off a challenge from Yohan Cabaye before slipping Ibrahimovic in on goal to win the game. Pogba is only 23. He will only continue to get better. It's scary to contemplate how good he could be in two or three year's time.
2) Ibrahimovic is worth his weight in gold
Zlatan blew hot and cold early on in his time with United, but he now has nine Premier League goals and has scored eight times in his last eight appearances in all competitions. On Wednesday night, when United most needed him, he rose to the occasion. In the summer, Mourinho determined that United's biggest problem last season was a lack of finishing, which was why he so heavily targeted signing the Swede.
As he continues to provide for United in these big moments, Mourinho's decision will only seem wiser. Ibrahimovic has never been a man known for being shy on confidence, but as these goals continue to fly in, his performances should only get better.
3) We still don't know who the real Crystal Palace are
Palace have been one the streakiest teams in the League this season. They find themselves on 15 points and in 16th place, which will do nothing to relieve the pressure on Alan Pardew's shoulders. Yet, the performance from Palace wasn't poor. They were dominated in the first half but were rather unlucky to go behind as Pogba may have been offside, and then responded brilliantly to get back into the game. Yet, they conceded painfully at the death, which will do nothing to help team morale.
Things will get no easier for them this weekend when Chelsea come calling at Selhurst and they also face a trip to the Emirates before the festive period comes to a close. Depending on how the next several weeks go, they could find themselves in another relegation dogfight.
4) Alan Pardew is in trouble
This has not been the easiest season for Pardew, and he may be on the hottest seat in the league. Palace have now won just one of their last 10 matches, with only five points garnered over that period. The manager has publicly feuded with his ownership group. Palace have scored 28 goals this term, fifth-most in the league, but have also conceded 30 goals, good for the third-worst defensive record in the league. How much longer does he last?
5) United continue to progress
Mourinho's time in charge of the Reds has been intensely frustrating. They have thrown away leads from leading positions time and again, prompting the manager to label them the unluckiest team in the league. Yet, the performances continue to be good, particularly when going forward, which pleases fans.
They are seven games unbeaten in the league, with two straight victories, and are on to the last-32 of the Europa League and the League Cup semifinals. Mourinho's United may not win the title, but they are on the right track.