Angelo Mathews says an inspirational session in the nets with Kumar Sangakkara laid the foundations for Sri Lanka's stunning Champions Trophy victory against India.

Sangakkara is retired from international duty, but the legendary Sri Lanka batsman is currently playing for Surrey and he took the opportunity to spend some time with his country's emerging youngsters before Thursday's crucial clash with India.

Still in fine form with Surrey, Sangakkara opted against coming out of retirement for the Champions Trophy, but the 39-year-old clearly still has an influence off the field.

Sri Lanka were thrashed by South Africa in their opening match last week but bounced back on Sangakkara's temporary home ground, chasing down India's total of 321 to win by seven wickets at The Oval.

It was Sri Lanka's joint highest ODI run chase and kept alive their hopes of reaching the semi-finals.

Danushka Gunathilaka, standing in for the injured Chamara Kapugedera, hit 76 off 72 balls while Kusal Mendis made 89 as the pair set in motion an unlikely victory.

And Sri Lanka captain Mathews revealed some tips from Sangakkara this week helped turn the tide. “Kusal met Sanga to get some batting tips because he is the king,” Mathews said.

“We all look up to him and take advice from him, all the batters. He taught us good things about how to play on these tracks.

“The guys met him, took a lot of advice and went out there and did it today.” Gunathilaka's ODI career-best innings was especially impressive as he would have been watching in the stands if Kapugedera hadn't been ruled out with a knee injury suffered in practice on Wednesday.

Gunathilaka and Mendis put together a 159-run partnership before Mathews (52) and Asela Gunaratne (34) finished the job with eight balls to spare.

In the midst of a major rebuilding project, Sri Lanka will clinch an unexpected place in the last four if they beat Pakistan on Monday.

“For Danushka to walk into a game knowing he wasn't even in the 15 until after Chamara got injured is impressive,” Mathews said.

“He had to step in against a very strong opposition and I was very impressed with how he batted. “He and Kusal played with a lot of freedom and that set us a platform and made it so much easier for myself and the middle order batters.

“Asela's little cameo as well really won us the game at the end so it was a fantastic batting effort. “