Portsmouth manager Alain Perrin said West Brom's need for points was the difference between the two teams after the Baggies' 2-0 win.
"The relegation situation was not our problem, our aim was to try and take some points to improve our position in the table," said Perrin.
"But I think the desire of West Brom was perhaps more.
"We showed we were professional in the way we went out to try and get points and there is a good spirit here."
Perrin added that the decision not to include striker Yakubu in the squad was due to his probable sale during the summer.
"We have some proposals so I think it was better for him not to play to avoid an injury. It was better for him and the club to stay at home," added the Pompey boss.