Midfielder Dario Rivero added the third early in the second half for Boca, who remain unbeaten after 27 matches going back to last season and have conceded only four goals in 17 matches in the Apertura championship.
Second-placed Racing Club were 11 points behind after Saturday's 2-0 win at Colon in Santa Fe and third-placed Tigre were 12 adrift before their match at San Lorenzo on Monday.
The win sealed Boca's 24th league title since the Argentine game went professional in 1931. It was their eighth since the introduction of two championships per season in 1991 and first since 2008.
Cvitanich, who began his career at Banfield before moving to Ajax Amsterdam and Pachuca in Mexico, struck in the 10th minute.
A corner to the far post was returned into the middle where the ball came back off the bar and was headed off the line as it pinged around the six-yard box like a pinball before Cvitanich blasted it through a swarm of defenders and goalkeeper Cristian Lucchetti.
Cvitanich volleyed his and Boca's second just before the interval and Rivero caught Lucchetti, who played for Boca last season, wrong-footed with a dipping shot from outside the box a minute into the second half.
Captain Juan Roman Riquelme, who had been out for more than a month through injury, came on as a second-half substitute before joining in mass celebrations on the pitch, in the stands and on the terraces.
"I promised [the fans] a championship and we delivered. I keep my word," Riquelme said in an on-pitch interview.
Boca coach Julio Cesar Falcioni won his second Argentine league title having won his first in charge of Sunday's opponents Banfield at the same venue two years ago.
Winning the championship also gave Boca gave another chance to dig fun at arch-rivals River Plate who were relegated in June and on Saturday lost 1-0 away to namesakes Boca Unidos.
The match was the last in the career of Hector Baldassi, Argentina's top referee who officiated at last year's World Cup finals in South Africa.
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