The advances in information technology of both hardware and software have allowed big data to emerge recently, classification of such data is extremely slow, particularly when using K-nearest neighbors (KNN) classifier. In this article, we propose a new approach that creates a binary search tree (BST) to be used later by the KNN to speed up the big data classification. This approach is based on finding the furthest-pair of points (diameter) in a data set, and then, it uses this pair of points to sort the examples of the training data set into a BST. At each node of the BST, the furthest-pair is found and the examples located at that particular node are further sorted based on their distances to these local furthest points. The created BST is then searched for a test example to the leaf; the examples found in that particular leaf are used to classify the test example using the KNN classifier. The experimental results on some well-known machine learning data sets show the efficiency of the proposed method, in terms of speed and accuracy compared with the state-of-the-art methods reviewed. With some optimization, the proposed method has a great potential to be used for big data classification and can be generalized for other applications, particularly when classification speed is the main concern.