Sebastien Loeb's Rally Mexico lead stands at a commanding 36 seconds going into the final day.
Citroen maintained its comfortable 1-2 formation through Saturday's final three stages, with Mikko Hirvonen running second to Loeb.
Ford's Jari-Matti Latvala was quickest on both runs through the Comanjilla stage, but after his delays earlier in the weekend he now needs a miracle to progress beyond his current third place.
Petter Solberg (Ford), Mads Ostberg (Adapta Ford) and Ott Tanak (M-Sport Ford) continue to fill the other top six places, with the latter now under no pressure as his fast-closing teammate Evgeny Novikov went off and removed a wheel from his car on SS20.