At the moment when the Portuguese coach must have thought the team's momentum remained negative, Manchester United secured the home side's opening Selhurst Park setback in league competition from February onward.
The Palace manager's players started strongly and deservedly took the lead through the French striker's retaken penalty. However they failed to convert superiority into goals and having failed to net versus Palace, Amorim's team countered with a rapid double through Joshua Zirkzee plus the former Chelsea player.
The match proved disappointing encounter finishing following a busy period for the Palace boss, who observed the Senegalese international leave injured with a serious problem before half-time.
Ruben Amorim probably contained his reactions subdued when proceeding down the tunnel directly following the final whistle.
Amorim had played down comparisons between his and Glasner's strategic methods in the buildup, while admitting that the opposition "simply perform things better than us|aspects superior to ours|elements more effectively".
His response to the poor performance versus reduced Everton was to change the flank players, with Amad Diallo moving to the right flank as Diogo Dalot assumed Dorgu's position.
The visitors likely felt an opportunity to profit considering they enjoyed three more days to prepare and nearly scored first inside the opening minute.
A long throw caused chaos inside Palace's defense but somehow Dean Henderson executed a reflex block near the net to prevent the midfielder.
The close shave served as a wake-up call for Palace following the midday start that was scheduled by the television schedulers.
Soon the chances started arriving thick and fast. Following wasted numerous attempts during European action, it looked could potentially not become Mateta's day after he sent attempts off target in the initial phase.
Yet amid days where negotiations regarding Mateta's contract extension hit obstacles, Mateta stepped up who provided the first goal.
One more perfect ball from the England international lured Leny Yoro into the challenge following an earlier superb interception to prevent the Spaniard, the young defender was forced to foul his compatriot in the penalty box.
Henderson re-emerged with head protection to block the sun from the setting sun however he'll experience frustration to have allowed United to equalise eight minutes post the break.
Glasner's team was unprepared by a quick Bruno Fernandes free-kick allowing the forward to bring under control while turning simultaneously to produce a shot that flew into the net.
After enduring a goalmouth scramble as the forward came close again at the wrong end, their afternoon got even better moments after while Zirkzee was tripped on the edge of Palace's box from the Palace defender.
A temporary uncertainty developed within the barrier when Fernandes rolled the free-kick to Mount permitting Mount to beat Henderson with a powerful drive.
Lacking the winger's speed to depend on, Glasner's side found it difficult to generate additional opportunities while the visitors managed to complete a crucial victory that means Manchester United leapfrog the Eagles to sixth position.