Achieving high quality electron beams in laser wakefield accelerators requires stable guiding of the intense driving laser pulse, which is challenging because of mode mismatching due to relativistic self-focusing. Here we show how an intense pre-pulse can be used to prepare the phase-space distribution of plasma electrons encountered by a trailing laser pulse so that it produces its own well-matched guiding channel, while minimising wakefield evolution. Controlling the propagation of high intensity laser pulses is an essential step in developing useful wakefield accelerators and compact radiation sources.