Ahead of the game at Getafe, Betis had a chance to extend their 100 per cent record at the top with a fifth successive win.
Betis blew chance to surge clear at the top in Primera Liga
Sevilla did their cross-city rivals Betis - and the Seville derby is the most intense in Spain - a favour by beating Valencia.
It meant Betis went into Monday night's game at Getafe with a chance to extend their 100 per cent record at the top of the league with a fifth successive win.
Following Manchester United's draw at Stoke City in the English Premier League, there was not a club in any of Europe's six biggest leagues who had won every league game so far this season. The spotlight was on Betis.
With Barcelona and Real Madrid both dropping points in recent weeks, the promoted side from Seville had a chance of going four points clear at the top.
Betis enjoy wonderful support and regular 40,000-plus crowds at home, but they were at a Getafe side who are the worst supported team in the league and frequently fail to attract five-figure crowds.
The green and whites were confident of success against Getafe - owned by the Dubai-based Royal Emirates Group - who had picked up just a single point from their first four matches.
They lost 1-0.
Pepe Mel, the Betis coach, whose top-flight experience is limited to 26 games at Tenerife a decade ago, was typically sanguine after the defeat.
His side have stayed top and that is the position he intends to be in when they visit the Bernabeu in two weeks' time.
They first have to overcome Levante at home this weekend - a Levante side who beat Real two weeks ago.