There is only one hurdle between Geraint Thomas and the overall victory in the 2023 Giro d'Italia, and that is the daunting and unknown mountain time trial ending on Monte Lussari on stage 20. Leading Primož Roglič by just 26 seconds, Thomas knows that that one more strong, consistent performance can secure him the overall victory in Rome.The Welshman impressed yet again in a breathtaking Dolomite finish at Tre Cime di Lavaredo. He was able to go with Roglič as he attacked and they distanced Almeida by another 20 seconds. Thomas lost three seconds to Roglič in the last-gasp surge to the finish line but insisted the result did not reflect his chances tomorrow.Going into Saturday's 18.6km Monte Lussari mountain time trial, Thomas leads Roglič by just 26 seconds with Almedia at 59 seconds."There was a lot of climbing and the last climb was especially tough," Thomas explained post-stage, going through the action of the day. Read moreGiro d'Italia stage 19: Primoz Roglic gains seconds in mountaintop maglia rosa battle Giro d'Italia: Start order for stage 20 Monte Lussari time trial ‘I got a bit of legs back’ - Primoz Roglic ready for final Giro d’Italia TT showdown "It was a tough, solid day but the guys rode really well again. We expected Jumbo-Visma or UAE Team Emirates to try for the stage but that didn't happen, so we were confident we could ride the stage."Thomas matched Roglič's low-gear surges and even tried his own kick on the final steep curve up the finish. However, it cost him three precious seconds."When I went with 400m to go, I realised after just 100 metres it was a long way at altitude," Thomas joked."I lost three seconds to Primož but I was happy to gain time on João. Now it's all to play for tomorrow, it's going to be super close."Thomas shrugged off a question about if he goes on to lose the Giro d'Italia by the three seconds he lost at the Tre Cime di Lavaredo finish. He believes the longer, gradual, paced effort needed for the mountain time trial is more his thing."The time trial will be a different effort. We did a sprint of a minute and that's Primož's forte. Tomorrow is a long effort, so it's different," Thomas said."The hardest part of the climb is five kilometres at 15% or something crazy. It's a decent advantage and I'd rather have it than a deficit but it's going to be super hard. Primož is riding well and Almeida is great at pacing himself, so it's not over. I'm going to have to get up there as quickly as I can."It's an unknown effort, we hardly ever do a mountain time trial but it's the same for everyone. I'll try and pace it all the way to the line. I hope I can finish it off."Thomas has a chronological and psychological advantage on Roglič but has to produce a perfect ride on the 11km flat roads, execute his bike swap with precision and then manage his effort on the steep climb to the finish.The riders can do a final training ride on the Monte Lussari course early on Saturday morning and Thomas confirmed he will practise his bike swap technique with the Ineos Grenadiers mechanics.He will start last in the maglia rosa and will have time checks on Almeida and especially Roglič. Thomas never races to power, preferring to listen to his body and pace his effort."I need to just focus on myself and get up that climb as fast as possible and hopefully that wins me the Giro. I can't say I'm looking forward to it but it'll be nice to watch," he predicted."I've also got to stay strong mentally because if I'm down on time, I've got to follow my pace that will get me to the finish as quickly as possible. Time trials are a big mental game and especially this one."