Defending champion Sebastien Ogier needs to score just one more point than Volkswagen team-mate Latvala to retain the title he won for the first time in 2013.
Ogier could have finished the job at his home rally in France earlier in October, but mechanical problems meant he was never truly in contention.
Latvala subsequently claimed victory and cut his deficit in the standings to 27 points.
With a maximum of 28 points available from each of the two rallies, Ogier will be confident of wrapping up the title before the final meet in Wales.
However, Latvala is not ready to concede defeat, despite the fact he has never won back-to-back races.
"I've never been in this situation with two rallies to go and as long as I still have a chance I will keep on fighting," he told the official WRC website.
"The characteristics of the route suit me. I like the rally and we have a good set-up for gravel and asphalt, with which I'm very comfortable.
"The surface is relatively hard on the gravel stages, but is covered by a fine layer of loose gravel. The road sweeper effect is particularly potent here. That could give me a slight advantage. On the other hand, the dust in the air could impair my vision."
Earlier this week Ogier stated that he is "absolutely convinced" he will retain the title in Spain and, after winning in Catalunya 12 months ago, he has every right to be confident.
Latvala led after the opening two days in the 2013 rally, only to see Ogier eradicate the lead and climb from fourth to first.
A victory for either driver would see Volkswagen equal Citroen's record of 11 victories in a single season. With the team having won all but one rally this season, that scenario looks well within reach.
Hyundai's Thierry Neuville is the only other man to have won a rally in 2014 and he will join the likes of Mikko Hirvonen (Ford), Kris Meeke and Mads Ostberg (both Citroen) in attempting to break Volkswagen's dominance.