Prevc secures overall World Cup victory
"This is the biggest moment of my life, I've made it. It was harder at previous events in Finland, I was more relaxed, more confident here and I enjoyed the jumps," the 23-year-old said after the event.
Clinching jumps of 139.5 and 139 metres, Prevc scored 325.9 points to claim his 19th career World Cup victory and the 13th this season.
The latter matches the record set by Austrian jumper Gregor Schlierenzauer in the 2008/09 season.
The defending World Cup winner of previous season, Severin Freund of Germany placed second (137 and 141.5m, 314.3 pts) in today's event ahead of and Norway's Daniel Andre Tande (140.5 and 139.5m, 310.9 pts).
Prevc is the second Slovenian ski jumper to win the overall World Cup after Primož Peterka completed the feat twice in the 1996-97 and 1997-98 seasons.
He will accept the Crystal Globe at the final meet of the season in Slovenia's Planica on 20 March after narrowly missing it last year.
Prevc demonstrated he would be aiming only for the top by sweeping the prestigious Four Hills Tournament and going on to win the Ski Flying World Championship at the Kulm hill in January.
He interrupted his winning steak on the tour of Finland, but made a big comeback at the hill in the former Kazakhstani capital.
"I came to the hill, got into tune with it soon. It the air it's similar to the Bloudek hill in Planica," Prevc said after winning Saturday's event in Almaty.