Kusal Mendis is determined to score a double-century for Thilan Samaraweera and help Sri Lanka salvage a draw on the final day of the first Test against New Zealand in Wellington. 

The Black Caps failed to take a wicket on Tuesday as Mendis (116 not out) and Angelo Mathews (117no) batted all day in an unbroken stand of 246 to take Sri Lanka to 259-3 - trailing by 37 runs. 

However, having battled through a lean period in all formats, Mendis is not content with just reaching a sixth Test hundred as he eyes a career-best knock for departing batting coach Samaraweera, who will be replaced by Jon Lewis after the two-match series. 

"I'm really thankful to Thilan because I was in a really low place - I had failed about 15 one-dayers, and still the coach [Chandika Hathurusingha] and Thilan aiya refused to drop me," he said.

"They let me play Tests again. I was only able to get here because they stood by me. Thilan goes after the next Test, but I'm really thankful to him. I was only able to do this because of them."

Kusal added: "I remember one time in Sri Lanka, I got out for 196. Thilan was coaching Bangladesh at the time. He told me: 'You will later realise what you've done. You've got more talent than that. To be able to score 200 at your age means you've got a big future.'

"Then when he had become our coach, I missed a double-ton again, against Bangladesh [making 194 earlier this year]. He told me the same thing again.

"Before this Test he told me: 'Before I leave, hit a double-hundred.' So I'm trying my best to score a double for him. He's helped me so much. Everyone in the team knows how much he's helped.

"Not just on the cricket side of things, but he's helped me personally as well."