That was until an injury to the 49ers' starting quarterback, Jimmy Garoppolo.
Below are the 49ers-Dolphins in-game injury updates.
QB Jimmy Garoppolo (foot, out)
Garoppolo exited the game after the 49ers' first offensive drive. Garoppolo was sacked and then carted to the locker room with an ankle injury. That left rookie quarterback Brock Purdy to enter the game.
San Francisco announced that Garoppolo is "questionable" to return.
Update: Garoppolo has been ruled out due to a foot injury, not an ankle injury, as initially reported.
DT Hassan Ridgeway (pectoral, out)
Hassan Ridgeway was shaken up in the fourth quarter, and walked off the field under his own power but favoring his right arm. Later, the defensive lineman left for the locker room.
San Francisco announced that Ridgeway is "questionable" to return with a shoulder injury.
Update: The 49ers announced that Ridgeway suffered a pectoral injury and has been ruled out.