"When you don't have the best eleven in the park that really affects you. Some of those guys are definitely impact players and we miss them big time," Mathews said, talking to Cricbuzz.
Sri Lanka had chased 322 to defeat India in the Champions Trophy, but the current side has looked a shadow of its former self.
"Losing the Zimbabwe series was a bitter pill to swallow. We have not had any momentum since then. The moment we get our momentum back, everything will fall in line," Mathews added.
India have not lost a game on the tour so far and have looked invincible so far,
"It's all about momentum. All what we need is to win one game and when that happens, I am sure we will turn things around. That will help us to overcome many things. All what we need to do is to win that one game to gain confidence. It is very hard to keep losing like this. The whole team is down. The way we have lost, in particular, has been disappointing. We have simply not been able to compete. We have lost before too, but we have competed well," Mathews added.
The all-rounder, talking about his own personal performance said he is disappointed with the way he has been dismissed in the past couple of matches.
"Personally, I feel very disappointed with the way I have got out especially after getting decent starts. I have been trying to score runs quickly rather than settling down. Really frustrated with my performance and only in the last game I was able to make a very small impact."
With Sri Lanka's hopes for direct quantification now all but out of their hands, Mathews said that qualification remains a major worry for the team.
"That is a concern, no doubt. We would like to win the next game at least rather than leave everything at the hands of West Indies. Whatever we can control we have to control. I must say that India have played outstandingly well. We seniors have to lift our games as we have not lived up to expectations." he said.
India: Virat Kohli (capt), Shikhar Dhawan, Rohit Sharma, KL Rahul, Manish Pandey, Ajinkya Rahane, Kedar Jadhav, Mahendra Singh Dhoni, Hardik Pandya, Axar Patel, Kuldeep Yadav, Yuzvendra Chahal, Jasprit Bumrah, Bhuvneshwar Kumar, Shardul Thakur.
Sri Lanka: Upul Tharanga (capt), Lasith Malinga, Dhananjaya de Silva, Dilshan Munaweera, Lahiru Thirimanna, Angelo Mathews, Niroshan Dickwella, Kusal Mendis, Milinda Siriwardana, Malinda Pushpakumara, Akila Dananjaya, Lakshan Sandakan, Thisara Perera, Wanindu Hasaranga, Dushmantha Chameera, Vishwa Fernando.
First Published: September 3, 2017, 8:40 AM IST