Carlo Ancelotti's side continued warming up for the Champions League final with a comprehensive demolition of their Basque visitors at the Santiago Bernabeu.
Bellingham scored the opener and played a part in Madrid's next three goals, two scored by Vinicius, finding his best form at the business end of the season.
Turkish teenager Arda Guler added a late fifth to put the cherry on Madrid's cake and moving them 17 points clear of second-place Barcelona.
Madrid celebrated their title with an open-top bus parade on Sunday but with the Wembley final a little over a fortnight away, nobody is letting their concentration slip.
Least of all Belgian goalkeeper Thibaut Courtois, who made a fine double save from Samu Omorodion in the opening minutes.
After missing most of the season with a severe knee injury, Courtois is hoping for a Champions League final start and boasts three clean sheets in three matches since his return.
Ancelotti selected the vast majority of his first choice line-up after resting them at the weekend, and Madrid's usual suspect opened the scoring. It was Bellingham, with his 19th league goal and perhaps his luckiest.
The England international directed Toni Kroos' cross towards the far post where Dani Carvajal was running in, but the ball sank directly into the net.
Madrid doubled their lead after Bellingham threaded a pass through for Eduardo Camavinga.
The French midfielder burst forward in the box and unselfishly squared for Vinicius to tap home when other players might have taken the chance to shoot.
Alaves midfielder Ianis Hagi, son of legendary Romanian playmaker Gheorghe Hagi, stung the palms of Courtois with a fierce drive at the other end.
The visitors have enjoyed a strong season and are safely ensconced in mid-table, avoiding the stress of a relegation battle.
However, Madrid dismantled them with consummate ease and Fede Valverde rattled home the third in first-half stoppage time after Bellingham played him in.
The Uruguayan midfielder hammered a strike into the top corner at the near post for his second league goal of the season, far fewer than his tally of seven last year due to his deeper role.
Five-star Madrid
Courtois denied Omorodion and Hagi again in the second half as he continued stating his case to Ancelotti, and he ended up making nine saves altogether.
Vinicius extended Madrid's lead after Bellingham played him in, lashing home his second of the night with a fine finish.
Rodrygo should have added the fifth but goalkeeper Jesus Owono denied him from close range after Vinicius teed him up, and so it was Guler instead after a deflected effort fell his way in the box.
Eder Militao and Carvajal ended the game with apparent issues in the only sour note for Los Blancos, who will hope they are minor problems at worst.
Earlier Mallorca, 15th, rescued a 1-1 draw at Osasuna to add one more point in their battle for survival. The Copa del Rey runners-up are seven points clear of the relegation zone.
Girona, third, face Villarreal in the final match on Tuesday, looking to move provisionally back above Barcelona.
