Lassila moved ahead of early leader Gil Membrado during the afternoon as changing conditions provided a demanding start to the five-round championship’s double-points finale.
Overnight rain had left Friday morning’s stages wet and slippery, with grip levels varying considerably from those experienced during reconnaissance.
Membrado adapted quickest and won the opening 22.94km Turquía test, edging Lassila by just 0.1sec. Carlberg responded on Nuevo Rere, beating Membrado by four tenths to claim his first bonus point of the weekend.
Lassila then struck on Hualqui. The Finn’s first stage win reduced Membrado’s overall advantage to only 0.6sec heading into midday service, setting up a close fight for the afternoon.
By then, however, the character of the roads had changed significantly. With the surface considerably drier for the second pass through Turquía, Lassila produced the decisive performance of the day. He beat Membrado by 13.9sec and turned his narrow deficit into a 13.3sec lead.
Carlberg was fastest again on the following Nuevo Rere test, but Lassila conceded only 0.8sec to the Swede and remained 14.8sec ahead of Membrado when the final scheduled stage was cancelled before the Junior WRC field reached it.
Membrado therefore holds second overnight after leading through the entire morning, while local driver Gerardo Rosselot sits third, 29.9sec from Lassila.
Rosselot spent the early stages readjusting to Ford Fiesta Rally3 machinery after recent experience in Rally2 and without a pre-event test, but remained consistently among the front-running pace on his home roads.
Immediately behind him, the battle between the championship’s top two could hardly be closer.
Ali Türkkan is fourth, 44.2sec from the lead, with Carlberg just half a second behind in fifth. Türkkan took a cautious approach through the difficult morning conditions, while Carlberg recovered from an initially tentative start to win two of the five completed stages.
Those fastest times could become important in the title fight.
Carlberg arrived in Chile leading Türkkan by only three points, 95 to 92, with Membrado on 71 and Lassila on 61. One additional championship point is awarded for every Junior WRC stage victory, meaning Carlberg has collected two so far in Chile, as has Lassila, while Membrado has added one.
The larger rewards will come at the finish. Classification points are doubled at the season finale, with 50 available for victory, while only each driver’s best four classification results from the five-round campaign count towards the final championship standings.
That leaves the title contest firmly open heading into Saturday, with Lassila’s Friday performance bringing the Finn further into an already close championship equation.
Craig Rahill completes the Junior WRC classification in sixth, 2min 15.7sec from the lead, after finding it difficult to commit fully in conditions which had changed substantially since reconnaissance.
Kerem Kazaz retired in the opening stage following a heavy impact on a jump. Kazaz and co-driver Corentin Silvestre were transported to hospital for precautionary medical checks.
Saturday brings the longest leg of the rally, with two passes each of Pelún, Lota and the 28.31km María las Cruces forming 139.2 competitive kilometres.