Bournemouth manager Lee Bradbury admitted he must now try and lift his players for the rest of the run-in after a stoppage-time strike from Tranmere substitute Adam McGurk earned Rovers a 2-1 win.
McGurk smashed the ball in off the underside of the crossbar moments after Bournemouth substitute Danny Ings thought he had salvaged a point for the Cherries.
Ings cancelled out Ian Goodison's opener with a stunning overhead-kick in injury-time, but McGurk won it for relegation-threatened Rovers seconds before the final whistle.
Bradbury said: "I'm very disappointed and the lads are really down. To get back in the game that late and then have a goal scored against us is hard to take and the team is very dejected.
"Now it's up to me to pick them up this week. The second half we did okay but the first half was unacceptable, nowhere near what we are about. It wasn't good enough.
"I told the lads that at half-time and second half we looked more like ourselves and took the game to them a bit more and created a few chances."