With flashbulbs popping from the crowd of 37,564, Sosa connected on a 1-2 pitch from Jason Marquis (5-4), who just happened to be wearing Sosa's old No. 21. The ball sailed 395 feet into the Rangers' bullpen, and reliever Akinori Otsuka retrieved it.
Anyone who saw any of Sosa's franchise-record 545 homers with the Cubs recognized his trademark hop as he left the batter's box, and his heart-tapping, kiss-blowing salute as he crossed home plate. He's come a long way since he belted his first career homer on June 21, 1989, also for the Rangers, and off Roger Clemens, who was pitching for Boston.
"The home run is probably the most revered stat in baseball, for whatever reason," Cubs manager Lou Piniella said. "You hit 600 of them, you've trotted around the bases a long, long time."
He's now the fifth player to hit 600, joining Hank Aaron, Barry Bonds, Babe Ruth and Willie Mays. Marquis is the 364th different pitcher to serve up a dinger to Sosa, who entered the game 4-for-12 lifetime against the right-hander. Sosa had reached on an error in the first inning and a fielder's choice in the third before connecting in the fifth.
"Everything clicked," Sosa said. "It was a special day. All the fans that were here behind me, that was awesome. I'll never forget this night. This night gave me a lot of joy."
It was not a night Marquis would like to remember. He lost his third straight decision and gave up six runs, four earned, on five hits and four walks over five innings. He hasn't won since May 9. Frank Catalanotto made matters worse after Sosa's blast when he connected on his fifth home run.
"I'm not getting ahead of hitters like I want to," Marquis said. "I'm not getting strike one as consistent as I was early in the year. I'm still getting the ground balls I want, but I'm going too deep in the counts and not allowing myself to get too deep in the ballgames."
Marquis also couldn't get comfortable on the mound.
"The slope was a lot steeper than I anticipated," Marquis said. "That's no excuse. I have to make an adjustment. Later in the game, I started throwing from the stretch even with nobody on because I felt a little more comfortable. I tried to make an adjustment. A couple walks early on in the game in the first inning, I was just trying to get a feel for the mound. I just didn't execute pitches like I needed to."
"He needs to step it up," Piniella said. "He wasn't throwing the ball like he was earlier in the year, and it's showing in his performance."
The Cubs hit a couple homers of their own, though none as historic as Sosa's. Alfonso Soriano connected on his 12th with two outs in the fifth, and Koyie Hill hit his first this year with two outs in the seventh, a two-run shot to straightaway center. Hill is just 598 shy of catching Sosa. Soriano has now hit 220 in his career. Does he ever think about 600?
"Myself? I don't think so," Soriano said. "I've hit 200 something in six years. I think that's a lot of homers. I can't imagine getting 400, 500, that's a lot of homers. Sammy Sosa hit 600 homers, that's a lot, especially in this game.
"Six hundred stolen bases, 600 homers, or 600 doubles, that's a lot," Soriano said. "You have to play a long time in this game, 14, 15 years, and stay healthy and put up those numbers every year. That's why I'm very excited about Sammy, he put up those numbers. I'm glad I saw it, and I'm happy for him."
Both of the Cubs blasts came off Rangers starter Kameron Loe (3-6), who gave up six hits and one walk over 6 2/3 innings.
The Cubs committed an error in each of the first three innings. Marquis walked the first two batters he faced and the Rangers loaded the bases with none out in the first. They tallied when Sosa reached on a fielding error by third baseman Mark DeRosa, and another run scored when Catalanotto grounded into a double play.
Turns out DeRosa never saw the ball. The vision in his left eye was blurred because of a vega-vasal episode.
"I felt like I was looking through a kaleidoscope out of my left eye," DeRosa said.
He had to leave the game after that inning, and was fine after cooling off.
"It was more heat-related, migraine, plus it blurred my vision," DeRosa said. "It scared the heck out of me when I was on the field. I was having blurred vision in my left eye. I came up here and within about a half hour, 45 minutes, I was fine. No big deal."
Another error led to a Rangers run with two outs in the second. Brad Wilkerson scored from third when first baseman Derrek Lee couldn't get a glove on Kenny Lofton's grounder, and the ball skipped between his legs.
"We didn't play very well at all," Piniella said. "We were actually pretty sloppy the first three innings, and then we got back in the game a little bit. We just didn't do a very good job tonight."