1. A method for analyzing a tennis session for game improvement using a portable device and a tennis analysis system, said method comprising: collecting information from said tennis session using said portable device attached to a racket used in a game for a plurality of strokes, said information includes at least one among acceleration of the racket, rate of rotation of the racket for x, y, and z axis, swing speed of said racket, time markers, and result markers; transferring said collected information from said portable device to said tennis analysis system using a communication interface; analyzing information relating to said plurality of strokes, where said analysis includes at least classifying said stroke, by said tennis analysis system; analyzing information relating to collections of strokes from said plurality of strokes to identify rallies, games, sets and matches played during the session, by said tennis analysis system; and generating a plurality of game statistics using information available from said analysis of plurality of strokes and said analysis relating to a collection of strokes from said plurality of strokes, by said tennis analysis system, wherein said portable device comprises of a processor, a sensor module including at least a gyroscope sensor and an accelerometer sensor, and a plurality of communication interfaces, and wherein said tennis analysis system comprises a tennis analysis engine.