Others certainly play a role, but at its core, baseball is a series of one-on-one matchups. A pItcher throws and the batter is left to decide whether to swing or take, attempting to reach base however he can. Kris Bryant and Carlos Martinez have had nine such occurrences. The final three took place on a Sunday at Wrigley Field int he heart of the September pennant chase as the Cardinals and Cubs raced toward 100 victories. Martinez dominated Bryant en route to an important win as the Cardinals attempted to close out another division title and fifth straight playoff appearance.

On September 20, 2015, the Cubs faced the Cardinals in a crucial game for the pennant race. The Cardinals sat five games ahead of the Cubs and four games ahead of the Pirates for the division. The Cubs had won five games in a row, including the first two in the series against the Cardinals, and were making a last ditch effort for the division title. A win, and the Cubs would be four games out with 13 to play—difficult, but not impossible. A Cardinals victory would put the Cubs six games out and make it nearly impossible to win the division.

Heading into September 20, the Cubs had won four out of the last five games they played against the Cardinals, and Martinez had started the only victory in that span. Since struggling against the division-rival Cubs and Pirates in back-to-back starts in May, Martinez pitched better than anyone on the staff. Sixteen of his last 20 starts had been quality, and he had more starts with 0 or 1 earned run (11) than starts with at least 2 earned runs. He had struck out 141 hitters in his last 133.2 innings and gotten his walk rate down to nearly 2.5/9 innings. His FIP and ERA during that time were an identical 2.56 as a starter to go along with a 56% ground ball rate.

Kris Bryant was a force from Day 1 in the majors. He struggled a bit in July, from August 1 heading into that September 20 game, Bryant was hitting .335/.410/.623 with a wRC+ of 183 and 11 home runs, including one in the game a day prior. In Bryant's first game against Martinez in May, he had two walks and a single. The next time the two tangled, Martinez got the better of him with a strikeout, a foul out to right field and a groundout. The two players were born less than four months apart, with that September start against the Cubs just a day before Martinez's 24th birthday.

When Bryant came to bat on September 20 for the first time, the Cardinals already had a 3-0 lead on the strength of home runs by Tommy Pham and Stephen Piscotty off Jon Lester in the first inning. Martinez's first pitch was a 97 mph fastball, per Brooks Baseball, down the middle of the plate that froze Bryant as the bat position when the ball hits the glove shows:

The next pitch: an 86 mph slider a little out of the zone. Bryant looks foolish:

After a wasted slider low and away comes back with a third straight slider, this one right in the zone:

The next time Bryant comes up, the game situation has changed a bit. The Cardinals are leading, but the score is now 4-2. After a trying and tiring third inning saw Martinez give up two walks, get visibly upset with the umpires strike zone, and give up a two-run single up the middle to Anthony Rizzo when Jhonny Peralta could not quite keep the ball in front of him. With runners at first and third and two outs, Martinez attacks Bryant with the same gameplan, this time a 99 mph fastball, and he gets the same result:

In the first at bat, Martinez followed up with a slider, inducing a Bryant whiff. Bryant does not pick up on the strategy:

Last time up, Martinez wasted a slider away. This time, on the 28th pitch of the inning, he threw a 100mph fastball. Save for foul-tipping the strikeout in the first plate appearance, Bryant made contact for the first time of the day on his fourth swing, getting a piece of the ball as it went to the backstop. After going fastball, slider, fastball, Bryant might be assuming another slider.

Martinez threw the ball 92 mph. It was a changeup. Again Bryant fouled it off.

Martinez has thrown Bryant four sliders to this point. Bryant has swung and missed on three of those four. On the next pitch he makes it four out of five.

An argument could be made that this very moment was when the Cardinals season peaked. Martinez navigated through a difficult inning--one where he would approach the umpire after it was over to apologize for showing his displeasure. The game was not yet over, but the Cardinals had ended the Cubs best rally before it could really blow up. Matt Holliday had pinch hit and was ready to return. Tommy Pham had not yet been relegated to the bench. The concerns for Michael Wacha and Lance Lynn were growing, but not yet a full roar. John Lackey was pitching well, and Jaime Garcia looked like he was actually going to get a chance to pitch in a meaningful postseason game again.

A few innings later, Yadier Molina would be injured at a play at the plate, and those pitching concerns for Wacha and Lynn would increase as Martinez would not feel right heading into his next game and his season would be over. The fantastic 100-win season ended with a disappointing loss to these same Cubs in the playoffs.

That strikeout was not the last at bat for Kris Bryant against El Gallo that day. In the bottom of the sixth, Bryant came up again, and at least for the first pitch, the strategy had not changed:

Strike one looking on a fastball for the third straight time. Martinez pumped another fastball to Bryant, just missing the top of the zone. When Martinez gave him another fastball over the plate, Bryant finally squared it up...and hit a 234-foot fly ball, per Baseball Savant.

Bryant averaged roughly 90 mph for his batted ball velocity on the year. On fly balls, he averaged 93 mph, per Baseball Savant, averaging about 330 feet per fly ball. Bryant's hit off Martinez registered at just 73 mph, and was hit so shallow it required a diving play from Jason Heyward to make the out. Bryant's ball was not the shortest fly ball Bryant had to the outfield. There are three shorter. Martinez owns the shortest, a 220 foul ball to right field. By batted ball velocity, it was weakest fly ball out for Bryant on the season.

Martinez threw Bryant 12 pitches in three at bats last September 20.

Bryant took five pitches. Three were called for strikes.

Bryant swung seven times. Four times he swung right through the baseball.

He hit just one ball in play—a weak fly ball.

Martinez and Bryant should face off many more times in the future, but for one day, Martinez won, owning both the match-up and the game.