The Tournament Starts!!

is chapter 180 of the Beelzebub manga.

Summary
The remaining sixteen couples in the competition draw out marked tennis balls from a lot drawing box; afterwards, explanations about the following portion of the competition are given to the couples. The students discover that they will be competing against each other in a bracket form of a tournament, with each doing various events against one another in order to advance, which will vary for each match.

In the first round for the tournament, Kanzaki and Yuka face off against an affectionate couple, Mitani and Oka, who mimic the two's princess carry technique from the previous event.

The two pairs step into a boxing ring set up in the gymnasium where they discover that they will need to perform an indirect kiss via bottles of carbonated water, which they will need to take turns emptying due to the intense carbonation in the drinks; upon realizing what an event this is, several of the delinquents remark about it.

The event soon begins for the first round and both pairs start immediately. While the Mitani-Oka pair are performing well, Kanzaki and Yuka struggle to move forward with the round due to their mutual embarrassment of being the one receiving the indirect kiss. After hearing a rude comment from the commentator, both delinquents deal a double drop kick to their opponents.

Following this momentary delay, they then finally make progress with the event as Yuka takes the first drink, consuming nearly a third of the entire bottle. However, just as Kanzaki is about to take his drink, Yuka, who realizes that she finds it to be more embarrassing for him to drink second, stops him from taking a sip. Subsequently, despite his explanations, she ends up attacking him towards their opponents and drinks the rest of their bottle on her own; therefore, they proceed to the second round.

Afterwards, Furuichi and Nene face off against Yamamura and Azusa for their portion of the first round. The pairs discover that they will need to play a gesture game to advance and the girls will need to explain to their partners about what it says on the board above; Azusa is supposed to indicate "squirrel" and Nene is supposed to indicate "poop". Neither girls end up doing any gestures for their partners. Instead, Furuichi mistakes their word as "underwear" and "panties" while Yamamura is flatly told what the word is. Due to Azusa's air-headed self, she inadvertently disqualifies her pair, allowing Furuichi and Nene to advance anyway.

The following matches then proceed, resulting in Izuma with Aoi and Tōjō with Shizuka advancing to the second round. Shortly after both matches end, Oga and Hilda step up for their portion of the first round.