How to find shortest string, first occurance it should return

I have this string. I m looking for td whose value contains  blabla with closing td.

<tr blabla><td>blabla big content</td></tr><tr><td>thisisnot</td></tr>

I want only this string <tr blabla><td>blabla big content</td>

I m using this regex in .net

<tr.*><td>blabla.*</td></tr>

I m new to regex... 

Can any one tell me the way out.