While Lee was tuning up for his postseason challenge as leader of the Rangers' staff, Guerrero was showing his former club he has lost none of his bat speed -- or love of the game -- in a 3-2 victory he personally delivered with a pair of run-producing hits.
"He's obviously had an incredible bounce-back year, and you can't help but wish Vlad well," said Angels manager Mike Scioscia. "Obviously, being in our division isn't great. On a personal level, this guy is one of the best and is having a season to remember. Vlad is a special person, and he's coming back and he's had a special season."
Torii Hunter could see it in his former teammate's eyes -- and the ferocity of his swing.
"Oh, yeah, you know he wants to stick it to us," Hunter said. "Who wouldn't? That's only natural. I'm pretty sure he loved the Angels, and they loved him. You can see it. He's trying to go deep every pitch."
Peter Bourjos, a one-man gang, tried to steal it for the Angels, bombing a tying homer in the eighth inning.
"He swung the bat well," Rangers manager Ron Washington said of Bourjos, who was a triple shy of a cycle. "He's a good-looking player."
The Rangers prevailed when Nelson Cruz doubled with one away against Jordan Walden in the bottom of the eighth and scored on Guerrero's line-drive single to left.
It was RBI No. 114 for Guerrero, who moved to Texas as a free agent after helping drive the Angels to within two victories of the World Series last October. The Angels had botched a rundown play with a chance to erase Cruz as he rounded second after his drive to right center.
Former Angels right-hander Darren O'Day moved to 6-2 with the win, while Walden dropped his first Major League decision.
Scott Kazmir, hoping to leave a positive impression on Scioscia in his final effort of a disappointing 2010 season, managed to duel Lee on fairly even terms.
Lee departed after seven innings with a one-run lead, but Bourjos tied it with a solo shot to left with two outs in the eighth against O'Day. It was his fifth homer.
Kazmir kept his team in the game as he continued to search for his former All-Star form, limiting Texas to two earned runs in 5 1/3 innings, issuing only two free passes along the way.
Bourjos' power and speed ended Lee's shutout bid in the sixth. The Angels' leadoff man slammed a double off the center-field wall, taking third when Julio Borbon misplayed it for an error. With one away, Bobby Abreu lifted a fly ball to medium left center and Bourjos cruised home with an unearned run.
Bourjos had given the Angels a scoring chance in the third with a two-out bunt single, steal and throwing error by catcher Bengie Molina. But Howard Kendrick grounded out to end the inning.
The Rangers seized the lead in the bottom half of the inning when Borbon and Elvis Andrus singled, putting runners on the corners as Borbon narrowly beat a strong throw to third by Hunter. Michael Young's sacrifice fly cashed in Borbon.
Back-to-back doubles by Cruz and Guerrero made it 2-0 in the fourth. The Rangers loaded the bases with one away before first baseman Mike Napoli turned a double play on Mitch Moreland's grounder, going to the bag for the first out and throwing home to Jeff Mathis to double up Guerrero.
Kazmir departed trailing by a run and leaving two runners to Francisco Rodriguez. The right-hander from Mexico, one of the Angels' finds this season, threw one pitch and got two outs, with Molina tapping into a double play.
Lee, tuning up for his American League Division Series Game 1 start against either the Rays or the Yankees, retired the side in order in the seventh. The hybrid-efficient southpaw was back in the form he'd shown in starts against the Yankees (one run, two hits, eight innings) and Mariners (one run, six hits, eight innings) before yielding four runs on six hits in five innings at Oakland in his previous outing.
Lee held the Angels to four hits and an unearned run in his seven innings, striking out eight. He wraps up the season with a strikeout-to-walk ratio of 10.28, an amazing 185 to 18 -- by far the best in the game. Lee is 12-9 with a 3.18 ERA in 28 starts with the Rangers and Mariners.
"He was in and out, hard and soft," Hunter said of Lee, a fellow Arkansas product. "He just goes right after you -- inside corner, outside corner. He doesn't make a mistake at all. You just don't hit him clean at all. It's always off the end of the bat or a jam shot. He's one of the best in the game."
With losses in 11 of his final 13 decisions, Kazmir finishes the season 9-15 with a 5.94 ERA. He plans to spend the winter in Arizona working on his physical conditioning and his command in an effort to carve out a rotation spot next spring.
"Kazmir battled," Scioscia said. "It's definitely a season he needs to turn the page on, and he will. I think it will be the most important offseason of his career, the most important challenge of his career. I think he'll get to work and get closer to the potential he can pitch at."
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.