A stripper packer for sealing a tubular of a wellsite is provided. The stripper packer includes an extendable housing, a packer, and a sliding window. The extendable housing has a passage therethrough to receive the tubular, and includes a piston operatively connectable between an upper and a lower portion of the extendable housing for selective movement therebetween. The packer is positionable within the extendable housing and sealingly engageable with the tubular. The sliding window is slidably positionable in the passage of the extendable housing and engageable with the packer. The sliding window is movable with the piston in response to pressure whereby the packer is sealable with the tubing.