A first-half goal from Ruben Castro proved decisive as Real Betis secured a 1-0 win at home to Athletic Bilbao on Sunday evening.Ernesto Valverde's men arrived in Andalusia having only lost one in five in LaLiga, with their opponents having won just one in five.But the home side emerged victorious to take them six points clear of the bottom three.The only goal came in the 18th minute as Antonio Sanabria teed up Castro and he was able to steer a low shot past Kepa Arrizabalaga in the Athletic goal.Antonio Adan made a smart save soon afterwards to deny Inaki Williams before Castro and Sanabria had efforts blocked in quick succession four minutes before the break.Adan made a fine save to deny Aritz Aduriz a headed equaliser three minutes into the second period and the Athletic forward came close again with another header on the hour mark, as his side enjoyed the greater possession and chances but could not find a breakthrough.Adan punched away a fierce shot from Iker Muniain as the clock ticked down before Ryan Donk was off-target with an effort at the other end, but Betis had already done enough to earn the win.ends