Beltre hit for the cycle and drove in three runs in Texas' 8-0 win over the Twins on Friday, improving to 12 for 18 with five homers, three doubles and a triple over his last four games.
Matt Harrison took a no-hitter into the seventh inning, and struggling Minnesota managed only three hits as the AL West-leading Rangers (74-51) won for the sixth time in seven games.
"We want to be hot the whole year," Beltre told the team's official website. "It's not like we pick spots. Of course, it's probably better if you heat up toward the end of the year. You want to keep swinging the bat good going into the playoffs."
Texas has won eight of nine versus Minnesota, and Dempster will try to help continue that run with another dominant performance against the Twins.
Dempster (2-1, 6.04 ERA) allowed four hits in eight scoreless innings of an 8-2 victory over Minnesota while pitching for the Chicago Cubs on June 10, but he's been inconsistent overall since being acquired by the Rangers at the non-waiver trade deadline.
The right-hander allowed eight runs in his first and third starts, though he tossed 6 2-3 scoreless innings of a 6-3 win over Boston on Aug. 7 before allowing one run and four hits in eight innings of a 5-1 victory over Baltimore on Sunday.
"That's what he's capable of doing,'' manager Ron Washington said after Dempster's most recent outing. ''He's not an overpowering guy. He has to execute his pitches, and (Sunday) he executed. As long as he executes them, he's going to be fine.''
Minnesota has been anything but fine of late, dropping 13 of 15 and scoring one or zero runs in three of its last four. Trevor Plouffe's single with two outs in the seventh ended Harrison's no-hit bid.
''Pretty much dominated by the young left-hander (Harrison) over there. He pretty much ate us up,''' manager Ron Gardenhire said. ''We were pretty much a non-factor in the game today. They pretty much dominated.''
Starting pitchers for the AL-worst Twins (51-74) have a 6.16 ERA during their slump, and Brian Duensing will try to improve that number Saturday.
Duensing (3-8, 4.46) is 2-6 with a 5.68 ERA in nine starts, though he limited Oakland to two runs - one earned - in six innings of a 7-2 win Monday.
"I'm feeling more comfortable," Duensing told the team's official website. "I've had a couple shaky innings here and there, but I thought tonight I was able to make some good pitches in key situations."
The left-hander is 2-2 with a 3.74 ERA in four career starts versus the Rangers, and has held Texas slugger Josh Hamilton to three hits in 14 at-bats (.214).