How does Descartes put forward a challenge to the empiricist view of reality?

In epistemology, there are two main schools of thought: the rationalist and the empiricist approach. The rationalist (like Descartes) believes that our main source of knowledge is reasoning and self-reflection, namely prioritising a priori knowledge (that is known independently of experience) - e.g. mathematical truths like 2+2=4. The empiricist, on the other hand, believes our main source of knowledge is through our senses and the external world, namely prioritising a posteriori knowledge (that is known only with experience) - e.g. there is a tree in my garden. Descartes, in his 'Meditations on First Philosophy', puts forward convincing arguments against the empiricist view (in Meditation I, mainly). He argues firstly 'from illusion' - that our senses deceive us sometimes, and perhaps the fact that I hallucinated an oasis on my visit to the Sahara last year means I cannot trust for sure that the tree in garden is really there. He then argues 'from dreaming' - that when we are in a dream we do not know we are there and everything seems real until we wake up - perhaps I am only dreaming now and there is no tree in my garden. Finally, he argues 'from deception' - that, for all we know, an entity could be deceiving us constantly and nothing in the outside world is as it seems. Due to these arguments, we can seemingly reject empiricism, because given it relies on information from the senses which could be wrong. It is not an adequate way to source knowledge.