Argentina's loss to Croatia opened up a huge door for Iceland and Nigeria to make headway in Group D, and it was the Super Eagles who took full advantage.
Ahmed Musa's second-half double gave Nigeria full control, while Gylfi Sigurdsson's missed penalty kick could loom large going forward, as Nigeria took a 2-0 triumph in Vologograd to move into second place in the group.
Iceland had the better of the play in the first half and looked to strike early. It nearly did through its superstar, Sigurdsson. His long-range free kick was earmarked for the upper left-hand corner of the goal, but Nigeria's 19-year-old goalkeeper Francis Uzoho made an acrobatic save to keep it out in the third minute.
Sigurdsson had another clean look from 18 yards in the run of play, with Game 1 goalscorer Alfred Finnbogason playing him into space before he took aim at goal, only to hit it right at Uzoho in the sixth minute.
The first half unfolded with a dearth of chances on both sides, though Iceland tried to break through in audacious fashion. With the ball looping in his direction, Birkir Bjarnason swung his right foot through it for a powerful volley, but it was one that was overhit and sailed over the bar in the 33rd minute.
Iceland was always the team that looked most likely to score, and it came close again just before halftime. Sigurdsson's free kick met Finnbogason in front of the goal mouth, but he wasn't able to get a clear hit on it, and the ball trickle harmlessly by the far post.
Nigeria flipped the script and came out firing seconds into the second half, testing Game 1 hero Hannes Thor Halldorsson right off the bat through Oghenekaro Etebo, whose low shot was saved well by the goalkeeper.
Nigeria's pressure paid off soon after. On a clinical counter, Victor Moses got free down the right before sending in a cross. Ahmed Musa kicked high to settle the cross and volley it to himself before blasting a right-footed shot by Halldrosson to secure the 1-0 lead.
Nigeria kept pushing and nearly got a second in spectacular fashion. Wilfred Ndidi let a long-range blast fly, and it appeared it would tuck under the crossbar if not for Halldorsson acrobatically tipping it over the bar.
A second nearly came for Nigeria in the 72nd off a corner kick. Leon Balogun leaped for a clear headed, but he put his chance over the bar, keeping the lead at 1-0.
The goal came soon after, though. Off a routine long ball out of the back, Musa beat Kari Arnason for pace, carrying into the Iceland box. Halldorsson came off his line trying to cut off the angle, but Musa rounded the keeper, kept his poise and finished from close range into an empty net to make it 2-0 in the 75th minute.
Iceland was gifted a chance to slice the deficit in half after the 80-minute mark off a freak play. Finnbogason was taken down trying to track down a loose ball heading away from goal toward the end line, in the Nigeria box. VAR confirmed the penalty, and up to the spot stepped Sigurdsson. He skied his chance way over the bar, though, spoiling the opportunity to slice into the deficit. Should goal differential come into play on the final day of group matches, that miss could loom large.
Croatia is already through from the group, with Nigeria sitting in second with three points and Iceland and Argentina in third and fourth, respectively, with a point apiece. Nigeria controls its destiny and would go through with a win over Argentina. For Iceland, it will require beating Croatia on the final matchday and hoping that Lionel Messi & Co. don't beat Nigeria by enough to overturn the goal differential edge, which Iceland currently holds by a single goal.
Here were the lineups for both teams:
Here are the rosters for both sides:
Goalkeepers: Francis Uzoho (Deportivo La Coruna), Ikechukwu Ezenwa (Enyimba), Daniel Akpeyi (Chippa United)
Defenders: William Troost-Ekong (Bursasport), Abdullahi Shehu (Bursaspor), Tyronne Ebuehi (Ado Den Haag), Elderson Echiejile (Cercle Brugge KSV), Bryan Idowu (Amkar Perm), Chidozie Awaziem (Nantes FC), Leon Balogun (Brighton), Kenneth Omeruo (Kasimpasa)
Midfielders: Mikel John Obi (Tianjin Teda), Ogenyi Onazi (Trabzonspor), Wilfred Ndidi (Leicester City), Oghenekaro Etebo (Las Palmas), John Ogu (Hapoel Be'er Sheva), Joel Obi (Torino, Italy)
Forwards: Ahmed Musa (CSKA Moscow), Kelechi Iheanacho (Leicester City), Victor Moses (Chelsea), Odion Ighalo (Changchun Yatai), Alex Iwobi (Arsenal), Simeon Nwankwo (Crotone)
Manager: Gernot Rohr
Goalkeepers: Hannes Thor Halldorsson (Randers), Runar Alex Runarsson (Nordsjaelland), Frederik Schram (Roskilde)
Defenders: Kari Arnason (Aberdeen), Ari Freyr Skulason (Lokeren), Birkir Mar Saevarsson (Valur), Sverrir Ingi Ingason (Rostov), Hordur Magnusson (Bristol City), Holmar Orn Eyjolfsson (Levski Sofia), Ragnar Sigurdsson (Rostov)
Midfielders: Johann Berg Gudmundsson (Burnley), Birkir Bjarnason (Aston Villa), Arnor Ingvi Traustason (Malmo), Emil Hallfredsson (Udinese), Gylfi Sigurdsson (Everton), Olafur Ingi Skulason (Karabukspor), Rurik Gislason (Sandhausen), Samuel Fridjonsson (Valerenga), Aron Gunnarsson (Cardiff City)
Forwards: Alfred Finnbogason (Augsburg), Bjorn Bergmann Sigurdarson (Rostov), Jon Dadi Bodvarsson (Reading), Albert Gudmundsson (PSV)
Manager: Heimir Hallgrímsson