Algorithms are increasingly employed by businesses as an integral part of their business models given the availability of big data and breakthroughs in artificial intelligence technology and application. While the competition landscape has shifted to a digital environment, questions have been raised as to whether the traditional competition policy tools, formulated in the analogue era, may nevertheless remain relevant in addressing algorithmic anti-competitive practices. In particular, the unilateral use of algorithms and algorithmic tacit collusion raises enforcement challenges for the competition authorities because of the inability of existing ex-post measures to adequately address these algorithmic anti-competitive conducts. This paper discusses these issues through a critical analysis of the relevant law, economics and computer science literatures.