Gernot Rohr watched helplessly as his Super Eagles team, along with most other African sides at the World Cup, were ripped to shreds due to their vulnerability at set-pieces.
The two goals conceded in the opening defeat against Croatia marked the fourth game on the spin that the Super Eagles had conceded from set-pieces. It was not good enough. The fans knew it, the media knew it, and obviously so did the coach.
In the build-up to last Friday's game against Iceland, Rohr and the team spent hours working on that vulnerability. And at both ends of the pitch, although the coach stressed that in the two years since he has been in charge, the side had not conceded from set-pieces (prior to the pre-tournament friendlies) because they had been working so hard on it.
So was it something to do with the quality of the opposition perhaps? In any case, against Iceland all that work paid off as the Super Eagles countered everything that came that way, prompting opposition coach Heimir Hallgrímsson to reflect: "They were very good in the air today, very good with set-pieces."
Most of that was due to the use of three centre-backs, including the imposing Kenneth Omeruo. Between him and William Troost-Ekong, they won 100 percent of the 10 headed clearances they went for, five apiece. Only Hordur Magnusson had more (8/8).
Omeruo also won five of six aerial duels, second only to Wilfred Ndidi, who won 6 of 7. As a matter of fact, of the five players who own two or more defensive aerial duels, Nigeria had four, with William Troost-Ekong (2/6) and Mikel Obi (2/4) the others. Only Kari Arnason (2/5) made it in there for Iceland.
This is in stark contrast to the Croatia game when not a single Nigerian player made it into the top five of the headed clearances list, and only Leon Balogun (3/3) and Brian Idowu (2/3) got into the aerial duels won top five.
Yes, there were still one or two hairy moments against Iceland, but Rohr said the key was not to panic: "If every time a set-piece comes there is panic, then there is going to be a problem," he told KweséESPN. "We just have to be calm and everybody know his position."
And so it proved.
But as they go into Tuesday's game against Argentina, it will be even more important they keep their wits about them in defending those set-pieces, winning aerial duels, and being aware and not falling for the gamesmanship of the South Americans.
Thankfully, there is the Video Assistant Referee now to review any dubious attempts by the Argentines to con the officials, and there will be.
Beyond that, defending those set-pieces cannot be over stressed. Of the seven goals Argentina have scored against Nigeria in World Cup encounters, five have been from set-pieces.
In 1994, Claudio Cannigia scored twice from two free-kicks as the Argentines came from a goal down to win 2-1, including a slick combination with Diego Maradona to take advantage of the naïveté of the Super Eagles to score the winner.
In 2002, Gabriel Batistuta stole in at the far post to head home from a corner-kick, and in 2010 it was a Gabriel Heinze header from, you guessed it, a corner-kick.
In 2014, Marcos Rojo also headed in the winner from a corner-kick. It was the second set-piece goal the Super Eagles conceded on the day, with Messi having given the Albiceleste a 2-1 lead from a free-kick.
Scoring from these situations is something Argentina have mastered, and they will keep knocking at the door on Tuesday. Balogun, Troost-Ekong, Omeruo and all the other players charged with defending set-pieces must be on their guard for the entire 90 minutes.
Francis Uzoho is young and inexperienced, but has shown that he can handle one-on-one situations. It may be asking too much of him to do the same for the duration against Leo Messi, but the defence can at least keep him protected. Their World Cup progress depends on it.