Cardinals 8, Cubs 7 (12). St. Louis began the game with Ken Hill, a starter who would go on to a fairly long career. The Cubs started Les Lancaster, who was primarily a reliever and would have a fairly short career.
The Cubs may not have had the better end of the pitching matchup, but they grabbed the early lead despite that disadvantage. Chico Walker led off the game with a single, stole second, and moved to third on a single by Mark Grace. Ryne Sandberg then doubled both runners home, though he was thrown out trying to stretch the hit into a triple. St. Louis made up half of the deficit on Todd Zeile's homer in the bottom of the first. Rick Wilkins opened the second with a single, and made it as far as third before being stranded; Lancaster then set the Cardinals down in order in the home half of the inning.
Chicago extended the lead in the third when Sandberg walked and stole second and Andre Dawson homered to make the lead 4-1. Lancaster worked around a hit by Jose Oquendo in the bottom of the inning, and the Cubs padded their advantage again in the fourth. Wilkins was hit by a pitch to start the frame. Shawon Dunston then hit into a forceout, but Oquendo committed a throwing error in trying for a double play, allowing Dunston to take second. One out later, Lancaster doubled Dunston home, chasing Hill from the mound in favor of Omar Olivares. Walker greeted the new hurler with a single that plated Lancaster and made it a 6-1 game.
Lancaster worked around a Pedro Guerrero single in the fourth, and walked and stranded Oquendo in the fifth. Meanwhile, Olivares set the Cubs down in order in the fifth, and Scott Terry allowed a George Bell single and nothing else in the sixth. After that, the next batter to reach was Tom Pagnozzi when Lancaster plunked him with two outs in the seventh; he would be left on first a batter later.
Sandberg led off the eighth with a double, but was doubled off on a line drive to center. The Cubs made a series of defensive replacements in the bottom of the inning (Walker from third to right, Jerome Walton in to play center, Joze Vizcaino in to play third, Doug Dascenzo from center to left), but none of them involved Lancaster, and the Cardinals made them pay for it. Milt Thompson, Ozzie Smith, and Zeile all singled with one out, bringing home a run. Guerrero struck out, but Felix Jose doubled, making it 6-3. Paul Assenmacher relieved Lancaster and allowed a two-run single to pinch hitter Craig Wilson; Pagnozzi singled as well, putting the tying run at third, but Assenmacher then retired Oquendo to end the inning.
Lee Smith worked around a Wilkins walk in the ninth (despite the fact that Wilkins advanced from first to second on a foulout to the first baseman, which is pretty impressive). Chuck McElroy relieved in the bottom of the inning and allowed a leadoff hit to Ray Lankford, but then coaxed forceouts from the next two hitters. Laddie Renfroe was summoned to go for the last out; by the time he got it, it was no longer the last out, as Zeile and Guerrero had singled to bring the tying run around.
Smith and Renfroe exchanged perfect tenths. Cris Carpenter set the Cubs down in order in the top of the eleventh, and Renfroe did the same to the Cards in the bottom of the inning. The top of the twelfth started with a Dunston single and a Dascenzo double, putting Chicago back in front 7-6. Renfroe hit for himself and popped up, and Walker grounded out, moving the remaining runner to third. Carpenter was then pulled, and Grace and Sandberg both walked against different pitchers before the second one (Willie Fraser) retired Walton to end the inning.
Renfroe remained on the mound for the bottom of the twelfth, and promptly gave up a double to Zeile and a single to Guerrero, retying the game at 7. Felix Jose singled Guerrero to third, Geronimo Pena was intentionally walked to load the bases, and Pagnozzi then singled Guerrero home to end the game.
I have mostly tried to avoid managerial second-guessing in these writeups, both because I have the benefit of considerable hindsight and because the game has changed in significant ways in the last 25 years. But I don't understand this particular game at all.
Les Lancaster had started in his last few appearances, but he spent most of 1991 and most of his career as a reliever. He pitched well at the beginning of this game, but he wasn't necessarily someone who was equipped to go deep into games on a regular basis. So I don't see why the Cubs wouldn't have had him on a shorter leash going into the late innings, five-run lead or no.
But beyond that, after using Assenmacher and McElroy for short stints, Jim Essian placed the game entirely in the hands of Laddie Renfroe, who would make a total of four appearances in his major league career (with an ERA of 13.50). You can't claim fatigue for the bullpen, because Mike Bielecki had gone 8 innings the day before this game, and Frank Castillo threw a complete game the day before that. And you can't claim he was saving them for the next game, because this was the day before the All-Star break.
Renfroe blew not one, but two leads, giving him a remarkable WPA of -.966. And as a result of his being left entirely to his own unrelieved devices on the mound, the Cubs lost a game that they should have won.