The tourists steadily picked up wickets during Friday's action, Lahiru Thirimanne, nightwatchman Dhammika Prasad, the usually attack-minded Tillakaratne Dilshan and Kumar Sangakkara all perishing before tea.

However, England were frustrated for the next 43.3 overs as Mahela Jayawardene and Thilan Samaraweera put on 90 for the fifth wicket.

Yet Swann ended their stand and at the close the hosts were 218-6 - a lead of 33 - and Prior believes the tourists must kick on in the morning in order to give themselves an attainable run-chase.

Strong position

"It was a tough day, frustrating at times but I think the way we stuck to our guns was absolutely fantastic and I think we deserved that couple of wickets at the end there to put us in a strong position for tomorrow," Prior told Sky Sports 1.

"In countries like Sri Lanka with the wicket playing pretty flat and the heat, you have to pick and choose the times when you go really hard as a unit and we knew that new ball was going to be a big time for us.

"The team picked itself up, got a lot of energy going, and we really deserved those two wickets at the end."

Although Prior knows England are in pole position to secure the win in Colombo, he realises the importance of claiming the final four wickets before focusing on their run chase.

"Going into the last day of the Test match, Sri Lanka lead by 33, six down, and we'll back ourselves to chase whatever they set," he continued.

"But first and foremost we have to take the four wickets.

"Hopefully we'll be chasing less than 150, but we know we've got the ability in the dressing room to chase down anything."

Straight

Samaraweera was bowled by Swann late on for 47 and he praised England's bowlers at the close of play.

"They bowled really well, straight to the batters, and it's not easy to dominate this wicket in batting," said the right-handed batsman.

"We were in a good position until the 89th over and lost two wickets. I think that is a crucial point."

Explaining the loss of his own wicket, he said: "I think it was a lack of concentration. I think Swanny bowled brilliant balls but I think this was not the best ball."

He added: "Tomorrow's first session is crucial. We have to get through without a wicket. I think 150 [would be] a very good lead. Anything can happen on the fifth day."