Ciro Immobile and Antonio Candreva were also on target as Italy stayed level with Spain at the top of European Group G. Both teams have 10 points from four games although Spain lead on goal difference.
Italy were quick off the mark when Alessio Romagnoli headed down a corner and Belotti turned the ball in from close range in the 11th minute. Belotti turned supplier one minute later when he headed a long pass forward into the path of Immobile who ran on and thumped his shot past Peter Jehle.
Italy, playing with a new 4-4-2 formation, sliced their way through the home defence and Candreva turned in the third in the 32nd minute after Mattia De Sciglio pulled the ball back from the byline.
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Belotti had a backheeled goal disallowed but was not to be denied and added Italy's fourth one minute before halftime when he ran onto Giacomo Bonaventura's chipped pass over the back and scored from a narrow angle.
Italy continued to dominate in the second half but the final pass repeatedly let them down to the clear frustration of coach Giampiero Ventura on the touchline. Liechtenstein stayed bottom of the group after their fourth straight defeat.
(This version of the story was refiled to fix headline)
(Writing by Brian Homewood, editing by Pritha Sarkar)
