Anisimov took a pass in front of the net from Namestnikov and scored with a wrist shot to make it 3-1 at 18:41 of the second.
"Especially in the second, I thought we kind of just left a couple guys right in front," Josi said. "That's how they scored their goals. They were all alone in front of [Saros] and we've got to be better in front of our net."
Tkachuk scored a power-play goal with a wrist shot off the right post to make it 4-1 at 1:20 of the third. Grimaldi got the Predators within 4-2 15 seconds later at 1:35.
Ryan Ellis' pass deflected in off Johansen's skate on the power play at 9:39 to make it 4-3. Josi went end-to-end, deked Senators defenseman Cody Goloubef and beat Hogberg with a backhand to tie it 4-4 at 13:07.
"I was just kind of skating down the wing and I was just kind of waiting for the [defenseman] to make a move," Josi said. "Once he made his move, I tried to go to the middle."
The Senators went 2-for-4 on the power play.
"Our power play wins us the game tonight," D.J. Smith said. "We've struggled in spurts, but it's been a lot better [as] of late. It gets two tonight, so it's good for them."