Josh Rosen's first start with the struggling Dolphins didn't go as expected.
Miami dropped its Week 3 matchup with Dallas, 31-6, as the second-year quarterback took over under center.
The Dolphins made the change heading into the weekend after journeyman Ryan Fitzpatrick went 0-2 through the team's first two games.
Rosen, who was playing behind an injured offensive line Sunday, finished 18-of-39 passing for 200 yards.
"I thought Josh made some good throws early," Flores told reporters after the game. "Look, that's a good defense. I thought he was tough, took a couple of hits, stood in the pocket. He gave us some opportunities on some throws. The drops didn't help him, that would have helped us as a team.
"We just didn't get it done but overall, I thought he played all right."
Miami was trailing just 10-6 at halftime, but too many missed opportunities in the second half led to Dallas running away with its third win.
Fitzpatrick saw a few snaps, as well, and went 2 of 2 for a quick 29 yards, but both quarterbacks failed to reach the end zone.
"We had a lot of opportunities," Flores said. "We had drops, fumble, dropped touchdowns, dropped interceptions. You can overcome one or two of those but when you put six, seven, eight of those together and they're plays that we can make, period. They're just plays that we can make and we don't make them, we have to start making those plays."
The Dolphins will host the Chargers next week at Hard Rock Stadium.