The Madrid side had shown signs that there was life yet in their bid to avoid relegation with a draw at Levante and an emphatic 4-1 win over Malaga, but those positive steps were undone a week later as they were massacred by Lionel Messi and company at the Nou Camp.
Defender Saul Niguez has insisted the team have put events in Barcelona firmly behind them and are looking ahead to the game with Sevilla, in which they will be hoping for a repeat of the performance they produced against Malaga.
"I think the Barcelona game was a one off," he told the club's official website.
"I think that after conceding so many goals, the team has improved, and we have to keep improving so we can get a clean sheet, and play according to our philosophy to get the three points."
But he recognised that Sevilla would be less accommodating opponents than Bernd Schuster's side.
"Getting the three points against Malaga was vital, but this is a little bit tougher, Sevilla are the next step up," said Saul.
The Atletico loanee was impressed with the level of support the team received from the fans inside a near-full Estadio de Vallecas against Malaga, and is hoping for a similar turn out from the Rayo faithful for the visit of Unai Emery's side.
"The Malaga game is the example to follow, if the fans are behind us like they were that day and the team plays with the same level of enthusiasm, we can really get at them."
Although ninth-placed Sevilla are in a far more comfortable position in the Primera Division than relegation-battling Rayo, they head to Vallecas in search of their first win in seven league games, and are likely to be feeling the emotional and physical effects of their 2-2 draw in Slovenia with Maribor in the first leg of their Europa League last 32 tie.
And they will be without suspended midfielders Vitolo and Denis Cheryshev, the latter sent off in last weekend's 0-0 draw with Valencia, although he was unlikely to have been fit for the match anyway after receiving a knock to his ankle against Maribor.