Bouanga converted from the penalty spot in the 59th to give LAFC (7-4-5), which had 56% possession and outshot Kansas City 21-5, a 2-1 lead.
Dejan Joveljic scored a goal for the fourth consecutive game when he ran onto a through ball played ahead by Manu García, exploded into the area and scored from near the penalty spot to make it 1-0 in the 39th minute.
The 25-year-old Joveljic, who scored 15 goals and had six assists last season and was acquired in February from the LA Galaxy in exchange for $4 million, is tied for third in MLS with 10 goals this season — five in the past four games.
Segura slipped a header — off a corner kick played into the center of the area by Bouanga — inside the back post in first-half stoppage time to make it 1-1 at halftime.
Olivier Giroud capped the scoring in the third minute of stoppage time, the 38-year-old’s second consecutive game with a goal.
John Pulskamp had four saves for Sporting.
Hugo Lloris stopped one shot for LAFC.
Kansas City (4-9-4) beat Houston 3-1 last time out to snap a four-game winless streak.
LAFC beat Sporting 2-0 on March 22. AP KHS KHS
