The Catalan club are 13th in the Primera Division but boast the seventh strongest defence in the league.
Javier Aguirre's side have let their guard drop at the back at times this season, shipping three goals against Levante and Sevilla, but have conceded just three times in as many league games, and kept a clean sheet in their last league outing, at Almeria.
And for Abraham, remaining solid in defence will be crucial if his side want to beat Valladolid.
"If we compete and keep a clean sheet, we will have a very good chance of getting a good result," he told a press conference.
"Earlier in the season teams found it difficult to score against us and right now we're on the right track to making that happen again. If we can achieve that, we'll be as strong as we were at the start of the season."
Valladolid go into Sunday's game on the back of two contrasting results in the last week.
Martinez's men beat fellow strugglers Celta Vigo 3-0 last Monday but were knocked out of the Copa del Rey by Vallecano just three days later, losing 3-1 in Vallecas.
Abraham warned that the Blanquivioletas are an unpredictable outfit.
"Valladolid are similar to Rayo Vallecano, they play good football and one day they can play well, the next they will play badly," he said.
Espanyol progressed to the last 16 of the Copa del Rey after seeing off Real Jaen, but Abraham stressed: "The cup is great, but the league is the most important thing and the match with Valladolid is vital."
Neither Aguirre nor Juan Ignacio Martinez have significant injury concerns ahead of the game. The Espanyol boss has a full squad to choose from, while the only doubt for Valladolid is midfielder Valdet Rama, still suffering from a calf problem.