Joe Ledley guaranteed Cardiff's spot in the Coca-Cola Championship play-offs with the only goal of the game against QPR.
Last season's dramatic collapse was still fresh in Cardiff memories after they picked up one point from their last four games to miss out on the play-offs by a single goal.
But there are no such worries this time round with Dave Jones' side assured of a shot at Wembley and the Premier League with two games to spare.
Ledley has suffered an injury-hit season and only recently returned to action following a double hip operation. But he picked the perfect time to score his third goal of the campaign, tucking away Mark Kennedy's cross with 10 minutes remaining.
Rangers sat fourth in October with ambitions of being in the promotion shake-up themselves, but after another traumatic season in west London they only recently climbed clear of relegation trouble.
Kelvin Etuhu could have doubled his side's lead but was denied by Radek Cerny, while at the other end Rangers substitute Lee Cook had the opportunity to spoil the party with a late volley but David Marshall pulled off a fine save to secure the win.