Kinsler became the first major leaguer ever with leadoff homers in each of his team's first two games, the first of four homers by the Rangers in a 12-5 victory over the Boston Red Sox on Saturday night.
Right after the Red Sox opted to intentionally walk slugger Josh Hamilton to load the bases with two outs in the fourth, Beltre made them pay with his ninth career grand slam. That capped a six-run outburst against John Lackey that put the Rangers up 9-3.
"I guess they were trying to take the best bat we had out of his hand," Texas manager Ron Washington said. "We are going to see that a lot. ... But we knew [Beltre] was going to be able to produce some runs. That's what he brings to our lineup. And many guys in our lineup can hurt you."
Nelson Cruz has also homered in each of the first two games for the Rangers, and new catcher Yorvit Torrealba hit his first Texas homer. Elvis Andrus had three hits including a double and a triple, drove in two runs and scored twice.
Kinsler who this year returned to the top of the Texas order where he primarily hit in 2009, extended his team record with his 15th career leadoff homer. He is the first player with leadoff homers in the first two games, according to STATS LLC.
"It's a lot of fun to get us ignited and get us going," Kinsler said.
It was another bad night in the Lone Star State for Lackey, the Texas native who often struggles back home.
Lackey (0-1) gave up nine runs and 10 hits in only 3 2/3 innings. The right-hander has a 6.78 ERA in 17 career starts at Rangers Ballpark, though he has 6-6 record there.
"You give up a leadoff home run, it isn't the start you want," Lackey said.
Colby Lewis (1-0), the Rangers' postseason ace last fall when they went to their first World Series, had four strikeouts while allowing three runs over six innings.
After Lackey quickly retired the first two batters of the fourth, Torrealba had a double and Julio Borbon followed with a triple into the right-field corner. Kinsler walked, Andrus had an run-scoring double and the Red Sox then chose to walk Hamilton, the majors leading hitter last season who already had two singles and an RBI.
"Anytime you're doing that, something isn't going well. But I'd have had a hard time answering it the other way around," Red Sox manager Terry Francona said. "If he hits a ball and you asked me why I didn't walk him, I wouldn't have had a good answer. He has had so much success against Lack."
Beltre hit a 1-0 pitch over the left-field wall.
After being an All-Star for the first time in his only season with Boston last year, Beltre turned down a $10 million option to stay and instead signed an $80 million, five year deal with the Rangers that has the potential for another $16 million in 2016.
Torrealba hit a two-run homer off reliever Dan Wheeler in the fifth.
The Rangers raised their AL championship flag before the opener Friday and got their rings in a pregame ceremony Saturday. They have now won their first two games for only the second time in 11 seasons.
Boston missed the playoffs last season for only the second time in an eight-year span that included two World Series titles. The last time the Red Sox lost their first two games was 2005, against the New York Yankees.
David Ortiz has homered in both of Boston's games, and drove in three runs to set the major league record for career RBIs by a designated hitter with 1,004. He matched Edgar Martinez's mark of 1,003 with his two-run homer in the second, then broke the mark with an RBI groundout in the fourth.
The homer by Ortiz put Boston up 2-1, and his grounder tied the game at 3-all.
Jacoby Ellsbury hit a two-run homer in the seventh off Rangers right-hander Mason Tobin, who made his major league debut replacing Lewis.
Gonzalez had three singles Saturday and is 5 for 9 so far. Crawford is hitless in seven at-bats with four strikeouts and a walk.
Hamilton made a nifty play for a stolen base in the third inning, sliding headfirst to the outside of the bag and reaching back to grab it with his hand to avoid a swiping tag attempt by 2B Dustin Pedroia. Hamilton's foot was still on the bag when Pedroia fell on top of him. ... Lackey's 34 starts against the Rangers and his most against any team. ... Lewis, who was 3-0 with a 1.71 ERA in four postseason starts last October, was represented by his brother during the pregame ring ceremony. ... Texas has 15 extra-base hits its first two games.