SEVILLE, Oct 19: Brazilian midfielder Denilson suffered a groin strain yesterday, leaving him doubtful for Real Betis's Uefa Cup second round first leg tie at Dutch club Willem II tomorrow.Officials at the Southern Spanish club, who paid a world record $35 million for Denilson this summer, said the Brazilian had torn an abductor muscle in his right leg and was extremely doubtful for the match.The Betis squad had been doing extra training after a crushing 0-3 home defeat by Celta Vigo on Saturday.Little has gone right for Denilson since he arrived in Spain. He was substituted after 22 minutes in Saturday's match and has been under a welter of media criticism for his lacklustre performances.He has shown very few flashes of the phenomenal dribbling ability that created his reputation in Brazil and has regularly been robbed of the ball while in possession.Betis have won just once in their first six games and are currently stuck in the first division relegation zone.