West Ham's dreams of reaching the Europa League quarter-finals are still alive despite a narrow 1-0 defeat to six-time winners Sevilla.
The Hammers put in a spirited performance in Spain against a side who have bettered Manchester United and Wolves in European competition over recent years, but will go into the second leg at London Stadium next week a goal down after Munir's superb strike earned Julen Lopetegui's men a narrow advantage.
There was a terrific atmosphere at the Ramon Sanchez-Pizjuan Stadium despite it not being a sellout, and the home supporters should have been treated to a goal in the opening five minutes.
A neat interchange of passing between Jesus Navas and Jesus Corona allowed the latter to swing a dangerous cross into the box, only for a flying Munir to plant his header wide of Alphonse Areola's post.
Minutes later it was West Ham who should have been ahead, as Nikola Vlasic missed a gilt-edged to open the scoring from close range. Declan Rice nodded Manuel Lanzini's whipped free-kick back across the six-yard box, only for Vlasic to power a diving header of his own straight at Sevilla goalkeeper Bono; Michail Antonio somehow mis-kicked the rebound instead of burying it in the back of the net.
The Hammers continued to impress and enjoyed good spells of possession in the first half, Vlasic flashing another shot at goal that Bono had to tip round the post.
Sevilla had their chances, too, but Munir was again unable to hit the target when presented with a decent opportunity, and Youssef En-Nesyri steered his header straight into the safe hands of Areola.
The second 45 minutes saw Sevilla show their experience at this level, and they gradually began to take hold of the game after Tomas Soucek had rifled a fierce effort straight at Bono.
Kurt Zouma's clumsy foul gave Sevilla a free kick just outside the Hammers' box, and the visitors switched off to allow Munir to ghost in from the edge of the area to steer a terrific half-volley past Areola and into the bottom corner.
Lucas Ocampos came close to doubling Sevilla's advantage twice, with En-Nesyri also having another header at goal, while at the other end Navas produced a superb block to deny Manuel Lanzini from close range.
Substitute Said Benrahma injected a bit of life into West Ham late on, but he wasn't able to create an equaliser for David Moyes's side - although the Scot can be proud of his players efforts in Seville.
Sevilla player ratings
1. Goalkeeper & defenders
Bono (GK) - 6/10 - Great reflex save early on to keep out Vlasic's header and did well to fist away Soucek's fierce drive to safety.
Jesus Navas (RB) - 8/10 - Made a terrific block to deny Lanzini from close range - tremendous from Sevilla's captain. Marauded up and down the right flank like a teenager.
Jules Kounde (CB) - 7/10 - Had his hands full with Antonio but was up for the task. Has a tremendous range of passing and skill on the ball, no wonder Chelsea have been linked.
Nemanja Gudelj (CB) - 6/10 - Didn't do anything wrong as such - but didn't really get to grips with Antonio and Vlasic early on. Looked a tad off the pace.
Marcos Acuna (LB) - 7/10 - Looked capable of making things happen for Sevilla. Classy in possession at times.
Joan Jordan (CM) - 8/10 - Progressed the ball nicely for Sevilla and switched the play superbly at times. Recovered the ball for fun.
Oliver Torres (CM) - 7/10 - Like Jordan, Torres specialises in the unspectacular - buzzed about keeping things simple.
Munir (AM) - 8/10 - Spurned a couple of chances in the first half but that was forgotten in an instant after a wonderfully controlled half-volley. Movement between the lines was impressive throughout.
Jesus Corona (RW) - 6/10 - Not as involved as it looked like he might be early on. Switched flanks to try and get more involved but the main threat actually came from Navas and Acuna.
Youssef En-Nesyri (ST) - 7/10 - A major threat in the air for Dawson and Zouma. Could have done better with a couple of opportunities but a good focal point.
Lucas Ocampos (LW) - 6/10 - The Argentine, similar to Corona, found it difficult to really influence the game - though you could argue he did little wrong.
Anthony Martial (75' for Munir) - 5/10 - The Manchester United loanee didn't have enough time to really get involved.
Ludwig Augustinsson (88' for Corona) - N/A
Rafa Mir (90+1' for En-Nesyri) - N/A
Subs not used: Dmitrovic (GK), Pastor, Salas, Carmona, Cruz, Sanchez, Romero, Martial
West Ham player ratings
5. Goalkeeper & defenders
Alphonse Areola (GK) - 6/10 - Handling was good when challenged by a powerful En-Nesyri header just before the half-hour mark. No chance with Munir's goal.
Ben Johnson (RB) - 7/10 - Not phased by the occasion whatsoever - cool, composed and displayed a maturity beyond his experience. Made some useful runs forward and solid in defence.
Craig Dawson (CB) - 6/10 - Struggled to get the better of En-Nesyri in the air and his awful concession of the ball almost cost West Ham a second. Defending was generally okay.
Kurt Zouma (CB) - 7/10 - Not the overwhelmingly dominant figure he has been of late - but still blocked, tackled and intercepted well. Booked for a bit of a clumsy lunge just before the hour mark, with the resulting free-kick leading to Munir's goal.
Aaron Cresswell (LB) - 6/10 - Recovered possession for West Ham on a number of occasions but wasn't able to influence play with dangerous balls into the box.
Declan Rice (CM) - 7/10 - Didn't disappoint on the big occasion for West Ham. Got his foot in when needed, read the game exceptionally well and kept up the tempo - brilliant considering he was ill earlier in the week.
Tomas Soucek (CM) - 7/10 - Fizzed a rocket of a shot at Bono early in the second half, though may feel he could have done better. Grew into the game.
Manuel Lanzini (CM) - 7/10 - Impressive on the ball in deeper and more advanced midfield areas. Great intelligence of what's around him at times.
Nikola Vlasic (RF) - 6/10 - Missed a glorious chance early on with a header that he really should have buried. Was a nuisance during the first half an hour but faded.
Michail Antonio (ST) - 7/10 - Put himself about brilliantly in the first half - stretching Sevilla's backline and drawing fouls. Wasn't as effective in the second as the hosts saw more of the ball.
Pablo Fornals (LF) - 6/10 - Gave possession away cheaply in the lead up to Sevilla's goal and was a little sloppy with the ball throughout.
Said Benrahma (67' for Vlasic) - 6/10 - Injected a bit of life and spark into West Ham's performance but couldn't help fashion an equaliser.
Mark Noble (83' for Lanzini) - N/A - Brought on late to help shut up shop.
Arthur Masuaku (90+1' for Fornals) - N/A - A stoppage-time change.
Subs not used: Fabianski (GK), Randolph (GK), Diop, Alese, Fredericks, Kral, Potts, Chesters, Perkins