Ryan O'Reilly cut it to 3-2 at 7:39, his 250th NHL goal, on a wrist shot from the left circle beating Samsonov to the glove side.
Justin Faulk's power-play goal at 9:30 tied it 3-3, a slap shot from the high slot.
"Yeah, we had some chances to win that game for sure," said O'Reilly, the Blues captain. "It's a little frustrating that way, but they're a dynamic team. Offensively they gave us a lot of issues there and took momentum too much at times. It's tough. We have to defend better against them.
"We kind of gave them a little too much and relied on 'Binner' to keep us in it. We scored some big goals, we kind of stuck with it there and ... it's a good point, but the position we're in right now, how tight this race is going to be, we need two points. It's disappointing that way, but some things to build off of."
NOTES: Nylander extended his point streak to four games (four goals, three assists). ... Toronto improved to 16-0-4 when leading after two periods. ... Thomas had an assist to give him 13 points (four goals, nine assists) the past 13 games. ... Kyrou returned after missing the past two games with an upper-body injury; he has 11 points (seven goals, four assists) his past five games and played 21:02. ... Blues forward Pavel Buchnevich had an assist in his 400th NHL game. He has eight points (four goals, four assists) the past seven games. ... St. Louis placed defenseman Torey Krug on long-term injured reserve Tuesday; he will be re-evaluated in six weeks. Krug was replaced by Rosen, who was a healthy scratch the previous seven games and played 14:02.