What mods do you have? I doubt it was a 99-00 Si since they don't have 'vtec si' sticker anywhere on them. Probably some fancy ricer who bought some stickers.
I'd say you were up against the AWD XR model Matrix. I could see how it'd kill an EX or DX. That AWD is a nice thing. Too bad they didn't add it to the 180hp model. The XRS would've been tougher to beat. It only lacks 12ft-lbs to your Accord, but is lighter and has more HP.
Good races though. And way to knock the ricers hopes down (referring to the wanna be Si). Maybe he'll up the ante and get some Honda Racing stickers.
93 Accord EX Coupe
Horsepower: 140 hp
Max Horsepower: 5600 rpm
Torque: 142 ft-lbs.
Max Torque: 4500 rpm
Weight: 2948 lbs.
03 Toyota Matrix XR (AWD)
Horsepower: 123 hp
Max Horsepower: 6000 rpm
Torque: 119 ft-lbs.
Max Torque: 4200 rpm
Weight: 2965 lbs.
03 Toyota Matrix XRS (FWD)
Horsepower: 180 hp
Max Horsepower: 7600 rpm
Torque: 130 ft-lbs.
Max Torque: 6800 rpm
Weight: 2877 lbs.
00 Honda Civic Si
Horsepower: 160 hp
Max Horsepower: 7600 rpm
Torque: 111 ft-lbs.
Max Torque: 7000 rpm
Weight: 2601 lbs.