Strange Event While Cruising!

I had my 2002 Diamante with 59,000 miles on cruise control at about 60MPH. I looked down for a second to get my drink from the the cup holder and heard this noise. I glanced at my dash and noticed that the tach was reading around 7500 RPM. As soon as I realized what was going on, it settled back to normal.

This has got me worried. Did this sudden but momentary RPM surge hurt my engine? Also, why did my car do this?

I can see a transmisson failure whereby the cruise attempts to keep a constant speed by increasing RPMs while the transmission is not engaging. However, the transmission seems to be operating flawlessly otherwise. Anybody got any ideas. I mean before I noticed this, the engine speed went 1500 at least over redline. This can't be good for the engine. In addition, I need to find out what the problem is so that it won't happen again, possibly reving the engine even higher.

Any help will be appreciated.