Beater Boxster clutch diagnosis...??

[Cebu]

I went for a ride this morning on the freeway arrived at my destination and parked. When I left and entered the freeway my RPM's jumped to 6000 and I was on 3rd. I rode for the next exit out and the car was smoking and and the car didn't seem to engage with the motor (slipping).

After I parked for awhile I started the car and there are no CEL on or any other fault light showing. I'm soliciting your opinions based on what I've said. Do you think it's the clutch gone bad? Prior to this incident the clutch never felt like it was slipping.

Any post test I can perform? I had Beater towed to my home and it's now in the garage. Since this isn't my primary car I'd like to do the repairs myself. I have tools and have access to more.

Any help would be greatly appreciated!!