The Thai doubles specialists have tested the Japanese duo before in a previous Davis Cup tie, as well as on the pro circuit, and are well aware of the danger they pose.

They anticipate the match could go up to five sets.

"It will be a very tough and close match, in which I think we have a 50-50 chance. It depends whose team plays better on the day," said elder brother Sonchat, who is 155 in the ATP doubles rankings.

Last year, the Thai duo lost a match featuring Iwabuchi, who was paired with Takao Suzuki, in three sets in the Davis Cup tie in Osaka.

"Matsui is a good serve and volleyer and Iwabuchi returns serves well. However, the speed of their returns is not powerful. If we keep our first serve percentage high and make good shot selections, we stand a good chance to beat them," said Sanchai, who is ranked five places below his brother on the doubles rankings.

Japan, led by captain Eiji Takeuchi, can re-adjust their doubles team at the last moment if they choose, as each country can change their players an hour prior to the competition. But the twins believe the visiting squad will keep the original selection.

"I think Japan will not change their mind because Iwabuchi and Matsui are better doubles players compared to Soeda and Motomura," said Sanchai.

Today's matches kick off with Paradorn Srichaphan versus Japanese veteran Gouichi Motomura at 2pm at the Rama Gardens Hotel. After that Danai Udomchoke will play Japan's No 1 Go Soeda in the second rubber.

UBC SuperSport will show live coverage of the matches from today to Sunday.