Offensive explosion continues as Mariners take three of four from defending champion Red Sox

Omar Narvaez stood and watched.

Can you blame him? The first-year Mariners catcher’s arms were extended, hips flipped open, bat hanging triumphantly behind his head. For a second or two, the 27-year-old Venezuelan was a 5-foot-11, 220-pound statue, gazing up into the seats as a blistered baseball bolted out of the ballpark. He watched, and so did everybody else, admiring a Mariners offense that has consistently, mercilessly clobbered the defending champs.

Narvaez’s three-run homer was the most emphatic moment — and the loudest crack of the bat — in a seven-run third inning for the Mariners on Sunday. Seattle (5-1) ultimately posted 12 hits and two homers, topping the Boston Red Sox 10-8 to…