Alonso, 24, is five home runs shy of tying the rookie record of 52, set by Aaron Judge in 2017. He is on pace to hit six more this season and set the new rookie mark. Alonso went 2-for-4 with two RBIs, two runs scored and a strikeout in the 3-1 win Monday at Citi Field in Queens.
"I just want to make the playoffs," Alonso told reporters. "That's something we still have a chance to do ... To be able to make it and have a chance to play for a ring, I think that would surpass any personal records."
Mets starter Jacob deGrom allowed three hits and one run in seven innings to pick up his ninth win of the season. DeGrom also had 11 strikeouts in the win. The star pitcher silenced the Diamondbacks in the top of the first frame.
Jeff McNeil grounded out in the Mets' first at-bat, prompting Alonso's first walk to the plate. The Mets first baseman missed a curveball with a swinging strike before settling in for the second pitch of his exchange with Diamondbacks starter Merrill Kelly. The right-handed pitcher tossed in another curveball on his second pitch.
Alonso ripped the off-speed lob over the left center field fence for a 389-foot solo shot. The blast had an exit velocity of 101 mph and left the field in 5.5 seconds, according to Statcast.
Alonso returned to the plate for his second home run in the bottom of the fifth inning. The Mets slugger also faced Kelly during that exchange. He began the at-bat with another swinging strike before ripping a 1-1 sinker over the left field fence for a 375-foot shot. That homer had an exit velocity of 110 mph and left the field in 3.9 seconds.
Alonso is now hitting .270 with 47 homers and 109 RBIs this season. Judge hit .287 with 52 homers and 127 RBIs during his Rookie of the Year campaign in 2017.
Ramos and Rosario each went 2-for-3 in Monday's win. The Mets host the Diamondbacks in the second clash of the four-game series at 7:10 p.m. EDT Tuesday in Queens.
"I'm impressed every day by Pete," Mets manager Mickey Callaway said. "I know everybody else is. Man, he is pretty good."