punch

Today at lunch in the dojo there were a couple of guys I hadn't worked with before, including one who is a semi-pro boxer getting ready for a fight soon.
At the end of the session I went one minute with him: mistake. Hands too fast it was all I could do to keep my head from getting knocked off, and then I took a hook to the ribs that didn't so much hurt as instantly knock all the air out of my lungs.
Dropped to my knees and tried to take a slow, deep breath, having flashbacks to the one and only time I played baseball as a little kid, and caught a hoppy line-drive right into the stomach. Same feeling of can't-breathe!, only this time I knew what to do.
Best part was, after me he went 3 minutes with another new guy, and 2 minutes into it, the semi-pro boxer (not the new guy!) suddenly stopped the fight and dropped to his knees -- he was panting, covered in sweat and totally out of breath!
Everyone told me: "If you just kept your guard solid, come into him more, and got aggressive, you would have tired him out!"
Good practice; at least now I know what it's like to square off with someone exactly my size but completely out of my league.