Guyette recorded the first five outs of the game on strikeouts and finished with nine on the night. Berger recorded three Ks over 2 1/3 innings and Melancon worked out of an inherited first and second jam in the ninth by striking out all three hitters he faced to end the game.
Guyette (4-1) picked up his team-leading fourth win of the year. The junior right-hander gave up three runs on six hits in 5 2/3 innings and walked only one. Melancon, who has struck out six of the seven hitters he has faced in two appearances against MSU this weekend, picked up his team-best third save of the year on Saturday.
MSU starter Todd Doolittle (1-1) was charged with the loss after giving up five runs on six hits in 2 2/3 innings. Doolittle walked four and struck out one in his first loss of the year.
Offensively, Arizona jumped out to a 5-0 lead through the first three innings with a run in the first, three in the second and one in the third. Five of Arizona's first six hits in the game went for extra bases, including three triples and two doubles.
The Bulldogs pulled within two with a pair of runs in the fourth and one in the sixth to cut the Arizona advantage to 5-3, but the combination of Berger and Melancon in relief and Wildcat runs in the seventh and eighth handed UA the four-run win.
Individually, senior Jeff Van Houten extended his hitting streak to 25 straight games with a 3 for 5-night at the plate. He drove in a pair of runs and hit his eighth double of the year.
Junior Trevor Crowe led off the game with a first-pitch triple to left field and added another three-base hit in the third to end up 2 for 5 with a RBI and two runs scored. Classmate Brad Boyer was the only other Wildcat to finish with multiple hits, going 2 for 2 with a triple, two runs scored, two hit by pitches and a RBI.
The lone blemish on the UA victory was the end of junior Jordan Brown's career-best 18-game hitting streak. Arizona's RBI leader finished the contest 0 for 4 with a run scored and a sacrifice fly.
MSU's Joseph Hunter paced the Bulldog offense, finishing 3 for 4 with two runs scored.
Arizona will attempt to sweep its third three-game series of the season on Sunday at 12 p.m. Senior Sean Rierson (2-1) is the scheduled starter for the Wildcats.