CANBERRA, Jan. 5 (Xinhua) -- Australia's declining No. 1 tennis player Lleyton Hewitt's coach Roger Rasheed on Friday announced his decision to quit, saying the pair could no longer work together.

He made the announcement via a statement a day after Hewitt's loss to Russian player Igor Kunitsyn at Adelaide International in south Australia and two weeks away from the Australian Open.

Reports said the pair had a sizeable argument immediately after the loss.

"This is the hardest decision I've ever had to make, but one I felt I had no choice but to make," Rasheed said in the statement.

"Within the current environment, I don't believe it is possible for us to get the results we are looking for," he added

The 37-year-old Rasheed was Hewitt's third coach following Darren Cahill and Jason Stoltenberg. Hewitt slip from world No. 1 to No. 20 under Rasheed's guidance since 2003 and failed to add to the two grand slams he won at the 2001 US Open when coached by Cahill, and Wimbledon 2002 under Stoltenberg's guidance.

In his statement, Rasheed said he still felt Hewitt capable of winning another major. "I believe in Lleyton as a player and still believe he's capable of winning grand slams, but I feel the only way I can make a positive change to his environment, and mine, is to walk away from one of the great coaching jobs," he said.