There has been a battle to see who leads the line for Pompey this season.
Summer signings Ellis Harrison and John Marquis have been the most regular players to take on the role.
And it is the former who has been the choice of manager Kenny Jackett for League One games in recent weeks.
But Harrison is more concerned with helping the Blues achieve success than cementing his own place in the team.
The striker said: “I’ll continue working hard to keep my shirt, but it’s certainly not a given. If I let up a bit then someone can snatch it from me.
“My job is to make it as difficult for the defenders as they make it for me, making sure that they don’t have an easy game.
“I’ll always make it hard by trying to press them and generally just trying to be as annoying as possible.
"I’d rather start fewer games and we got promoted, than every one and we end up finishing down in 10th."
“Everyone in the squad wants to go up this season and that’s always more important than the needs of any individual player.
“I’d rather start fewer games and we got promoted, than every one and we end up finishing down in 10th.
“We’re within touching distance at the moment and because we’re not currently in the top six, are out of the spotlight a bit.
“You saw Luton and Barnsley do so well last season, but it does seem to be a lot more open this time around.”
Pompey’s promotion challenge continues with a trip to face the division’s basement club on Saturday.
Harrison said: “We played Bolton at home earlier in the season and I thought they looked really good.
“We need to go there with the same mindset that we’d have against sides like Ipswich or Rotherham.
“You can’t just turn up and expect to win because no team is going to roll over and hand you three points.”