Alex Nuss followed with a single to bring Hamm home, then Nuss scored on a single by Riesen.
Haven got on the scoreboard with a run on two hits in the fourth inning, but rallied for three more runs in the sixth on three hits and a Hillsboro error.
Jacob Fish picked up a save by starting the seventh inning and retiring all three Wildcats he faced and preserving the win for Riesen (3-1), who gave up three earned runs on seven hits and a walk while striking out two.
Hamm and Nuss each went 2-for-3 with a run batted in to pace Hillsboro?s seven-hit attack.
In Game 2, Daniel Jost put Hillsboro ahead 1-0 when he led off the bottom of the first inning with a double, advanced on a sacrifice by Frick, then scored on a ground out by Hamm.
On the mound, Jost tamed the Wildcats until the top of the third, when they touched him for a pair of runs on three hits.
In the fourth inning, Haven took a 3-1 lead when the leadoff hitter reached on an error and eventually scored on a wild pitch.
The Trojans countered with one run on a single by Nuss and a double by Isaac Leihy.
Frick, who had relieved Jost with two outs and the bases loaded in the fourth, found himself in trouble in the fifth when he loaded the bases on a double and two walks. Three runners eventually scored to extend the visitors? lead to 6-2.
Hillsboro added a run in the sixth when Riesen was hit by a pitch and came home three batters later on a single by Tyler Ediger.
Frick (1-2) absorbed the loss. He was charged with three runs, all earned, in a total of two-thirds of an inning. Facing eight batters, he gave up two hits, walked two and hit two.
For the game, four Trojan pitchers combined to hit six batters and gave up eight base hits and three walks while striking three.
Meanwhile, Hillsboro?s offense was limited to five hits, three hit batters and one base on balls. Jost led the Trojans, going 2-for-4 with a double and a run scored.
Regionals?Hillsboro was scheduled to compete at the Class 3A regional in Hoisington on Tuesday. The Trojans, seeded third with an 8-8 record were to play the home-team Cardinals, seeded second at 10-7, in the semifinals of the five-team tournament.
On the other side of the bracket were No. 1 Halstead (10-4), No. 4 Lyons (6-8) and No. 5 Haven (5-13).
Results of Tuesday?s games will be posted on the Free Press Web site as soon as it becomes available.