Barcelona would have been confirmed champions had Real Madrid dropped points at the RCDE Stadium in Cornellà. Hansi Flick's side had beaten Osasuna in Pamplona on Saturday night and were waiting.
Instead, Vinicius ensured they will have to wait until next Sunday at a minimum — though Madrid's task remains a near-impossible one, trailing by 11 points with four games remaining.
The Brazilian delivered the kind of individual performance that has defined his season's best moments. He broke the deadlock on 55 minutes, exchanging passes with substitute Gonzalo García before cutting inside two defenders and finishing low into the near post. The second arrived on 66 minutes, a sweeping first-time finish into the top corner after a perfectly timed Jude Bellingham backheel. Espanyol goalkeeper Marko Dmitrovic had no answer to either.
Vinicius posted a message for Real Madrid supporters on social media immediately after the final whistle.
"To the death with this club. We have to keep going. We will return to the top."
He expanded on the mood inside the camp when speaking to RMTV.
"We worked very well this week and we knew we were going to win. It hasn't been a good season, but we're working and in every game we can change things for next season, which I'm sure will see us return to the top."
With one eye already on the Camp Nou, he was clear about the preparation underway.
"We're going to work very well this week to put in a performance like this one."
Head coach Álvaro Arbeloa, who praised Vinicius unreservedly after the match, also acknowledged the wider context.
"He had a great game, scoring two superb goals, and was the leader of the attack, a total threat. Every time he gets the ball he's very aggressive, very intelligent. A fantastic player, a born leader, a team-mate everyone loves."
Vinicius has now scored 21 goals in 51 appearances across all competitions this season, with 16 of those coming in 34 La Liga matches. It is his most prolific campaign in terms of league goals. The return has come in the second half of the season, with the Brazilian having consistently improved as his partnership with Kylian Mbappé — absent on Sunday through injury — has evolved.
Espanyol, now without a win in 17 league matches, remain 13th, five points above the relegation zone with four games left.