The 6ft 5in ball-winner whom Fulham fans nicknamed 'The Wardrobe' during his three seasons at the Cottage, said: "I came here for a new challenge and I'm very pleased with the start I've made.
"I'm enjoying myself doing the job I'm paid to do - with a lot of very good players around me."
Diop, who made his Pompey debut in a goalless draw with Liverpool, has had a four-match unbeaten run with Pompey - three of them wins, including his appearance as a substitute in the 1-0 Carling Cup success at Burnley and a dynamic performance in the 7-4 romp against Reading.
But he warned: "It will be a very different game at Fulham than the one against Reading. I don't think we will go forward as much and it will be a big test for us because Fulham had a hard game at Chelsea last week and took a good point.
"Maybe a draw would be a good result for us but I think it will be a good game."