It was a cruel blow for the U's at the Hawthorns as two late goals won it 4-3 for the home side.
Goals from Chis Coyne and Medy Elito gave the U's a 2-0 lead but Phillips and Brunt leveled things up before half time.
Kevin Lisbie put the U's ahead again but Morrison and Bedner won it for the Baggies with late goals - the U's front man now has as many league goals this season as in the rest of his career.
After last week's drubbing at Norwich, this was the U's fighting back.
They may have spent long periods under the cosh but it looked like, until the dying moments, that they might escape with a 3-2 victory.
The dramatic conclusion to the match saw it end in heartbreak once again, as the season of tough breaks took another bitter twist for Geraint Williams and his men.
The mathematics don't look great for the U's now and the prospect of near neighbours Ipswich being the ones to deliver the hammer blow lingers on the horizon.
At a wet and windy Hawthorns, Williams rang the changes in the U's defence and bought Chris Coyne and Pat Baldwin back into the starting eleven.
Adam Virgo and Bela Balogh made way for them after the U's suffered a 5-1 defeat at Norwich last weekend.
Captain Karl Duguid returned after injury to replace Kem Izzet in midfield as Williams looked to provide an upset against Tony Mowbray's Baggies.
WBA were the division's top scorers and are also in the semi final of the FA Cup and were themselves looking to move up into one of the automatic promotion positions.
Virgo, Balogh and Izzet were all on the bench, along with Scott Vernon and Mark Cousins, who returned to the squad after recovering from appendicitis.
While relegation wasn't a mathematical certainty for the U's, games are running out for them to get the necessary points to avoid the drop.
The game started with the rain and wind showing no sign of abating and it was the hosts who took command from the off.
Within thirty seconds, they should have been ahead but Brunt volleyed over from a good position.
On four minutes, the U's had to replace Baldwin after a shoulder injury forced him off, with Adam Virgo taking his place alongside Coyne. The home pressure continued but the U's defence held firm.
With their defenders working over time in defence, it was a U's defender who opened the scoring at the other end on thirteen minutes.
Coyne acrobatically scored with an overhead kick after a Dean Hammond free kick wasn't cleared.
The goal shocked the home side but there was more to come as Medy Elito scored his first ever goal in league football to put the U's 2-0 up.
He received the ball on the edge of the box and after a touch to compose himself, he rifled a left foot strike into the top corner.
The home support wanted to see an instant reaction from their men but the U's held firm and a quiet fifteen minutes followed the two goals.
It sprung tlo life though after thirty five minutes as the home side got themselves right back in the match with two goals of their own.
First, Kevin Phillips score at the far post from a Hoefkens cross and then Brunt made up for his earlier miss by drilling a left footer into the bottom corner of Dean Gerken's goal.
Gerken then kept the U's level with a stunning save from Phillips before he smothered another shot just before the half time whistle.
Both managers would have wanted their sides to carry on attacking in the second period but concentrate in defence when the opposition were on the ball.
That was how it turned out for the beginning of the second half as the U's defended with discipline to twart the Baggies.
In fact, the most notable incident of the first fifteen minutes of the half was when Geraint Williams was sent to the stand for dissent.
It was the U's who sparked to life after seventy five minutes as Kevin Lisbie made it 3-2 with his sixteenth of the season.
A Dean Hammond corner was met by Jackson, who's shot was saved by Keily but Lisbie pounced on the rebound to score.
With the crowd slipping out in droves, the home side dug deep and won the match in the last five minutes.
Morrison struck with his right foot before Bedner won it with a smart header.
It was a cruel blow to lose after such a battling performance and the U's can be proud of how they performed against one of the promotion favourites.















