"It was a paradise," Sri Lanka's former star batsman said of the famed stadium, hailed as one of the most picturesque in the world with its stunning views of the historic Galle fort's ramparts and its Indian Ocean setting.
Now it is a wreck.
The 10-metre (33 feet) wall of water that hit the field left behind a bus, three vans, two cars and four boats -- "big boats", said Warnaweera, who is also the ground curator, surveying the mass of tangled debris still strewn around.
The 10 nets used by schools and players for practice are flattened. The indoor artificial turf centre, the only one in Sri Lanka's south, is gutted and unusable.
Warnaweera's carefully cultivated flowers and orchids have disappeared from their crushed pots and the fish pond is full of sludge.
"This is like losing my family. This is my first love. I don't have the words to describe this damage, the disaster," he said.
Warnaweera's, 21 groundsmen and seven other staff used to spend up to 15 hours a day working at the stadium, which seated more than 10,000 fans for international matches with temporary stands erected.
"Because of our love for this ground, we didn't want to go anywhere else."
Now, they are transfixed by the damage.
In the shell of Warnaweera's office sits a huge water tank.
"Tell me, how did that get in here?" he said with a note of incredulity. "We are going to have to knock down a wall to get it out."
On the day disaster struck, an Under-15 schoolboys match between a Sri Lankan and an English side had been set to begin four minutes after the tsunami descended.
The players were on the field and able to scramble to safety, but the father of one of the English boys was killed as he sat in a bus. The toll could have been much higher if they had still been inside.
Warnaweera said the players had a long-running joke about the nearby sea one day engulfing the ground, which was originally built as a racetrack in the 1830s and was transformed into a cricket field in 1865.
"Finally, it has happened. The worst thing is even now if someone says the sea is coming we don't doublecheck to see if they are joking -- we just run."
The current Sri Lankan side, which cancelled its tour of New Zealand after the tsunami disaster hit, has already visited and were "stunned", he said.
On Wednesday, the players launched a fund to aid tsunami survivors which they hope will be supported by cricket fans around the world.
Warnaweera was Galle's first-ever Test player -- he represented Sri Lanka from 1985 to 1995 -- and was instrumental in putting the stadium on the international circuit in June 1998.
It has until now been a lucky venue, with Sri Lanka winning seven of the 11 test matches here, drawing two and losing two. Australian player Shane Warne took his 500th wicket here during Australia's last tour.
"It was my dream to make this an international Test ground, and somehow we did it, with a lot of difficulties," Warnaweera said. "And now, within such a short period of time, we are left having to face this."
The stadium was also a vital boost for Galle's economy, with hotels, guesthouses and restaurants packed out during international matches. Warnaweera reckons more than 200 local families were supported because of its presence.
Rebuilding will cost at least 300 million rupees (3 million dollars), he estimates. It will be a massive job.
For a start, about six inches (15 centimetres) of soil must be removed from right across the field and replaced. All of the drainage systems must be rebuilt from scratch. Maintenance machinery, computers and files are destroyed.
But a few items have been spared. Warnaweera proudly points out a photograph of the opening day of the first Test match, hanging on the wall of his office. The two-metre high watermark on the wall runs right across it.
And while cricket-mad Sri Lankans grieve for the more than 30,000 Sri Lankans killed by the tsunami, many are also sparing a thought for the loss of Galle's pride and joy.
Hotel management student Harsha Fernando, 24, who once played here as a schoolboy, dropped by to see the damage for himself.
"If you take 100 Sri Lankans, 95 of them are cricket lovers. This is one of the best grounds in Sri Lanka. But what to do now?" Fernando intoned.