The utilisation of non-Saccharomyces yeasts in co-inoculation and non-thermal technologies for must sterilisation is becoming increasingly prevalent due to its notable utility and potential. This approach optimises the fermentation process, facilitates the production of wines with distinctive characteristics and enhances their stability. Two trials were conducted concurrently, designated as A and B. The same red must was utilized in both trials, with one undergoing UHPH treatment and the other serving as the control. The non-Saccharomyces yeasts were identical in both trials. In Trial A, different percentages of initial inoculum were employed with respect to the total volume of must to be fermented, with the objective of evaluating the influence and competitiveness between yeasts. Trial B was designed to investigate the impact of two nutrients that provide vitamins, energy and protection from oxidative stress on the development of these yeasts and their metabolic expression. A microbiological analysis was conducted, along with oenological parameter measurements, acidification assessments, volatile compound analyses, and spectrophotometric evaluations. It was observed in both trials that the prevalence of Lachancea thermotolerans (Lt) was longer than that of Metschnikowia pulcherrima (Mp), and that the use of quercetin + thiamine had a positive effect on yeast growth. Furthermore, the combination of Lt and Mp yeasts demonstrated remarkable synergy, resulting in the production of a substantial quantity of lactic acid (>5 g/L). With regard to aroma compounds, the UHPH must exhibited a nearly twofold increase in ethyl lactate. Additionally, the TPI was observed to be 8-10% higher in wines derived from UHPH musts, indicating that this technology may potentially safeguard against oxidation.