Well, he did say he’d win. It just wasn’t in the way he wanted.
Episode 12 of Season 2 (or Episode 25 as a whole) of Boku no Hero Academia (My Hero Academia) opens with the various scenes earlier where Bakugo’s eagerness to defeat Todoroki and Izuku have been pronounced, such as when Izuku beat him during their first testing assignment. In comparison to him, Todoroki thinks to his mother and the fight with Izuku. But his thoughts are driven off as Bakugo stumbles into his room and tells him to bring everything he’s got, which Todoroki mentions Izuku telling him as well and questions Bakugo on if he was always that helpful at the detriment of himself. Bakugo, naturally, dismisses it and tells him not to hold back again since he wants everyone to know he beat Todoroki at his best.
When the match begins, Todoroki goes for a big ice attack to bury him, but Bakugo tunnels his way out and manages to get the first blow. However, when Todoroki refuses to use his fire after hearing his father tell him to use it, Bakugo gets pissed that he won’t come at him as hard as he did Izuku. And, despite a momentary flare-up, he basically throws the match and gets wrecked by Bakugo turning himself into a human missile.
So, Bakugo wins but its not how he wanted to win since Todoroki didn’t go all-out against him. He’s so angry that they had to chain him down for the award ceremony, like he’s a feral animal. Todoroki gets second place, and while Tokoyami and Iida share third place, the latter had to leave to go see his brother after his defeat by Stain. All Might hands out the medals and gives them advice on how to further their development as heroes before the students get two days off from school.
Iida goes to visit his brother in the hospital, who was in a touch-and-go surgery and can only apologize to him that he was defeated, despite being someone who his brother looked up to. As for Todoroki, he goes to visit his mother in the mental hospital that she was committed to for the first time since they were split apart and vows to rescue her from that place as the first step in becoming a hero. In comparison to them, Uraraka gets a visit from her parents in order to throw her a celebration for doing so well, Izuku has lunch with his mom, who admits to passing out seven times after the Calvary battle because of what he did to himself and makes him realize he needs to hurry up and master One For All, and Bakugo is still pissed off as the episode ends.
So concludes the tournament arc at halfway through the season, with one more to go. It ends on a somber note for Iida, his brother severely injured in the aftermath of his encounter with Stain. Nothing good can come from his final words, so while everyone else has a relatively positive note to end on his is outright tragic.
As for Bakugo, his drive to win carries him far into the matches, but we can see from his flashbacks that Izuku is still a sore spot for him. And it makes sense, since he ultimately brought out the best in Todoroki, who Bakugo wanted to beat when he was going all-out. Even in the face of his overwhelming power, Bakugo couldn’t manage that and its an outright insult to him.
Meanwhile, Todoroki is in a place of confusion but seeks to rectify that by visiting his mother. His father, being a bastard, basically had her committed and the only way for him to get himself together after that is to face his past. By the way, that girl who was in his house was his older sister.
As for Izuku… stop worrying your mother and master One For All.