Even when the Baltimore Ravens don't put all their effort into winning a preseason game, they can't lose.

Despite sitting just about every key player on the roster for Thursday night's preseasons opener against the Tennessee Titans, the Ravens won again. They extended their NFL record by winning their 21st straight preseason game 23-10. The Ravens haven't lost a preseason game since 2015.

Last year the Ravens won their 20th straight preseason game to break the record of 19 set by Vince Lombardi's Green Bay Packers from 1959-62. Even though John Harbaugh didn't downplay the streak last year, he also wasn't going to risk his front-line players to injury to keep it going.

After taking on a remarkable amount of injuries last season, the Ravens decided to sit 32 players on Thursday according to Jeff Zrebiec of The Athletic.

Even with all those players out the Ravens started fast. They cashed in a recovered fumble for a 4-yard touchdown run by Mike Davis for a 7-0 first quarter lead.

The Titans rallied, with rookie quarterback Malik Willis making several highlight plays. Willis had a fantastic 7-yard touchdown run, the Titans added a field goal for a 10-7 lead. Then with 35 seconds left in the half, Ravens quarterback Tyler Huntley lofted a pass to the end zone that was brought in by undrafted rookie Shemar Bridges for a nice touchdown. That was a turning point.

In the second half, the defense held the Titans' third-stringers out of the end zone. The big play was an interception with the Titans in Baltimore territory, as Ravens cornerback Daryl Worley hauled in an underthrown pass at the 2-yard line. Baltimore led 20-10 in the fourth quarter when another interception near midfield practically put the game away.

It's hard to win 21 in a row in any sport, even if the games don't matter in the standings. The Ravens' streak is a curiosity, but it's still impressive in its own way. And it's still alive.