Thilan Samaraweera revealed he had makeshift opening batsman Tillakaratne Dilshan to thank for his strong performance on day two.

Samaraweera hit a superb 159 and held Sri Lanka's middle-order together after fast bowler Iain O'Brien had given the visitors an encouraging start by removing Mahela Jayawardene in the second over of the morning.

Samaraweera ton put Lankans in control

Jayawardene added only six to his overnight 108, but Samaraweera ensured a healthy total for Sri Lanka, producing an 86-run stand for the fifth wicket with Angelo Mathews (39) on the second day of the first Test against New Zealand in Galle.

Daniel Vettori then claimed four quick wickets, including Samaraweera, in the post lunch session as the home side folded for 452, but Sri Lanka hit back to leave New Zealand struggling at 87 for two at stumps.

Dilshan, shunted into the opener's role for the first time in his career, had slammed a quick-fire 92 on the opening day to set the tone for Sri Lanka, while Samaraweera and Jayawardene built on that platform with a 166-run stand for the fourth wicket.

"I have Dilshan to thank because he set the momentum in this game," Samaraweera said.

"We were in some trouble at two for 16 and the wicket was aiding the bowlers quite a bit, but Dilshan batted really well.

"Because of his innings, Mahela and I were able to bat normally and without too much pressure. After I reached my hundred and with the time lost and a possible declaration in mind, I dominated the bowling."

"I have changed my approach"

Samaraweera reached his century off 223 deliveries, but his next 59 runs came off just 54 deliveries.

Samaraweera said his ability to change gears quickly was the result of an alteration in his way of thinking.

"I was mostly a very defensive batsman and then I was dropped from the side for the series against England in 2006," he said.

"I then worked with coaches and it resulted in a change of mindset. Now I'm always looking to score runs and that has helped my game tremendously. I think the key to my success is the hard work and the change in approach."

With New Zealand already two wickets down in their first innings, Samaraweera is hopeful his team can swing a result from this Test.

"The ball always does a bit on this track on day three and four," he said.

"There usually is swing for the fast bowlers and turn for the spinners. I think we were in a similar position in the Test against Pakistan and we did get a favourable result there so I think its possible here too.

"The spinners will prove a handful, but I think the key is the fast bowlers. If they pick up early wickets in the morning, we will be in a good position to force a result."