Other forms: unsurpassedly
Anything unsurpassed is the very best, superior to anything else. If the play you're watching is unsurpassed, you've never seen one that's better.
When one thing surpasses another, it goes way beyond in quality or achievement, often exceeding what you could've imagined. So if something (or someone) is unsurpassed, it's never been bested — in fact, it's the very greatest. This adjective is great for accomplishments that have never been outdone, like soccer star Pelé's unsurpassed record of the most World Cup wins.