Continuity mistake: A rare sight, the Nankatsu keeper actually parries something. When he does that he ends up on the ground, and his face is clean. He gets up, and his face is muddy. (00:18:30)
Continuity mistake: When Sanae waves at Tsubasa to cheer for him after Roberto's comedy bit with Ryo (telling him he wished he got injured earlier) the kid to her left has red hair instead of its proper dark color. (00:14:20)
Continuity mistake: When he vows to show the true Shuutetsu soccer to the opposing team, Genzo is wearing again the gloves he didn't have on the bench. (00:10:30)
Continuity mistake: The patches on Sanae's flag change position when she decides to wave it when she nearly throws herself down from the railing. (00:03:45)
Other mistake: After the first extra time, only 8 players (plus the keeper and Ryo) are back to the bench for all the pep talk and chat. (00:16:55)
Continuity mistake: Wakabayashi is still on all fours, dejected after being bested by Tsubasa. He lost his baseball cap parrying the shot in the right corner, but now both his beret and his wounded pride are towards the opposite side of the goal. (00:05:00)
Factual error: In this episode we have a random person showing up and being admitted to the team and playing as substitute on the spot, with nobody protesting. He puts on the (sweat-soaked, presumably!) uniform of another player and just goes ahead without any check from the referee or assistants. Given that the match is between two schools without necessarily having the official football federation involved, it is understandable, but they do not even ask the opposing coach if they are OK with something so obviously outside of any established rule. And they are still playing in a packed stadium, with official referees and even a radio commentator! Only in anime.
Other mistake: The linesman's flag as he hands the ball to Taki is unreasonably tiny. (00:18:45)
Audio problem: When Urabe gets in the field to ask to be a substitute, western dubs (verified in the Italian and spanish dubs) have Ryo (or "Bruce") ask him who he is. Ryo knows perfectly well who Urabe is, and they played a friendly match just a couple episodes before too. (00:06:45)
Continuity mistake: Ishizaki kicks the air to show that the injury is no biggie, and then clutches the injured ankle. Which was the right ankle, but his hand is on the left one. (00:04:50)