The day of the tournament arrives. The duke instructs Tosilos how to vanquish Don Quixote without injuring him, and the field is prepared for the combat, as spectators from far and near gather to witness the event. Tosilos, resplendent in his armor, mounted on a spirited charger, accepts the terms of the challenge, which are to marry the daughter if he loses or to be released of obligation if he wins. Tosilos, however, suddenly gazes in admiration at Rodriguez's daughter, and while Don Quixote begins to charge, calls to the marshal of the field that he has decided not to fight and will marry the lady right away. The joust is called off, and even though Tosilos is recognized as the wrong man when he removes his helmet, the mother and daughter accept the marriage proposal. Seeing the duke so astonished, Don Quixote assures him that enchanters always transform the faces of their opponents, and if he would wait two weeks, the footman will change back into the original lover.
While Don Quixote prepares to leave the castle in search of adventure, the duke's steward presents Sancho with a purse of 200 crowns. At the moment of departure, Altisidora steps up to Don Quixote and sings him a mock farewell. Accusing him of hard-heartedness in love, she goes even further and suggests that he has stolen her three handkerchiefs and two garters. Completely unruffled, the knight assures the angry duke that Altisidora is taking petty revenge for her unrequited love. Sancho says that the handkerchiefs were given him, and then the maiden remembers that she is wearing the garters. Dignified despite this latest jest, Don Quixote departs for Saragossa.