Evanilson, Dango Ouattara and Antoine Semenyo struck before halftime for the Cherries to take control of the game. Taylor Harwood-Bellis headed home a consolation for Saints after the break.
Martin barked afterwards: "There was a lack of fight, lack of spirit, lack of courage, lack of intensity, lack of aggression - it was just unrecognisable for us. The response to a setback was so poor. It's really hurt me, the first-half performance.
"It's only on me, I obviously didn't prepare them well enough. Once you get over the emotion of the night and the hurt from the first half, you've got to learn from it.
"Now we have a choice to make - we either feel sorry for ourselves or we respond properly and work even harder to get better. That is a choice - and I trust we have enough characters in there and good guys in there to make the right choice."
He also snapped: "I have to question myself. I thought I made enough of a deal about how Bournemouth approach the game and how they are good at certain things but it looks like we were unprepared and considering the work we have done is crazy.
"I will never ever blame a group of players, we're together but I didn't like what I saw and am hurt by the lack of spirit and fight, that's nothing I've not told the team. It's my problem to sort out.
"I didn't identify my team in the first half in terms of attitude, spirit and fight. I didn't get this far as a player or a manager on just talent, it's about mentality and I've not passed that on enough to the players.
"At half time I asked if they could please show they wanted to run and fight for us as a group, the staff and for each other. At least they did that, and that takes a bit of courage, so I thank them for that but I shouldn't be thanking my team for fighting and running."