McRae, the former world champion, started the last leg of the event only three seconds behind Liatti, the former European champion, and increased the pressure to snatch the lead on the penultimate stage.
His measured performance eventually gave him his third championship victory of the season by seven seconds. He also became the first British driver to win the rally and salvaged second place in the final points table after a mixed season in which he has crashed as often as he won.
"It was a bit of a close fight," McRae said. "There was never any breathing space, but it was a good day for me.
"After the year we've had it's good to win the last two rallies. The last stage was the worst. I slid a bit wide on one corner and I thought I was going to have another accident to add to this year's tally."
In the battle for third place, Belgium's Bruno Thiry held off his compatriot Freddy Loix, despite a serious hydraulic problem with his Ford.
Tommi Makinen, the world champion from Finland, made sure of fifth place, but was unable to match the leaders on asphalt roads that were not suitable for his Mitsubishi.
CATALUNYA RALLY Final standings: 1 C McRae (GB) Subaru Impreza 4hr 14min 20sec; 2 P Liatti (It) Subaru Impreza +7; 3 B Thiry (Bel) Ford Escort Cosworth +1min 18sec; 4 F Loix (Bel) Toyota Celica GT4 +1:35; 5 T Makinen (Fin) Mitsubishi Lancer +1:52; 6 P Bernardini (Fr) Ford Escort +3:10; 7 K Eriksson (Swe) Subaru Impreza +3:41; 8 O Gomez (Sp) Renault Megane +4:02; 9 R Madeira (Por) Toyota Celica GT4 +4:59; 10 A Medeghini (It) Subaru Impreza +6:38.
WORLD CHAMPIONSHIP Final standings: Drivers: 1 Makinen 123pts; 2 McRae 92; 3 C Sainz (Sp) 89; 4 Eriksson 78; 5 Liatti 56. Manufacturers: 1 Subaru 401; 2 Mitsubishi 322; 3 Ford 299.Reuse content