Once Shelby and the Dolphins built a 15-point lead, the Baltimore Ravens couldn't quite catch them either.
Miami intercepted a pair of deflected Schaub passes to score two touchdowns 20 seconds apart late in the first half Sunday, and held on to win 15-13. The Ravens moved into Dolphins territory twice in the final six minutes but failed to score.
The Dolphins (5-7) managed only eight first downs but improved to 4-4 under interim coach Dan Campbell, and ended a streak of five consecutive losses to the Ravens (4-8).
The score was 0-0 when Reshad Jones intercepted a pass batted by defensive tackle Jordan Phillips to set up the game's first score. On the next play, Ryan Tannehill hit a leaping DeVante Parker at the goal line for a 38-yard touchdown.
Three plays later, the 280-pound Shelby batted a pass in the air, caught it and ran 22 yards to the end zone for his first NFL touchdown.
It was the second pick-six in as many games for Schaub since he replaced Joe Flacco, who is out for the season with a knee injury.
Miami mounted a goal-line stand in the second quarter, and repeatedly turned away the Ravens down the stretch. Olivier Vernon totaled 2 1/2 sacks, one on third down with the Ravens nearing field goal range and five minutes left.
Baltimore recovered a fumble to get the ball back, but failed to pick up a first down, and Justin Tucker was wide right on a 55-yard field goal try with 2:42 to go. Tucker is the second-most accurate kicker in NFL history.
The Ravens again took over at their 20 with 20 seconds left and were unable to reach midfield.
Injury-plagued Baltimore lost despite outgaining Miami 375-219. Schaub threw for 308 yards.