The Texans took over around midfield after Jacksonville's Chad Henne couldn't complete a fourth-down pass and needed only two plays before Johnson's scoring reception handed them the victory.
Johnson made 14 catches for 273 yards and Schaub finished with a career-high 527 passing yards, five touchdowns and two interceptions for the AFC South-leading Texans (9-1), who overcame a 14-point deficit in the fourth quarter en route to their fourth straight win.
Henne came in for an injured Blaine Gabbert and fired four TD passes for the Jaguars (1-9), ending with 354 passing yards.
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