Carlos Alcaraz battled past unseeded Australian Jordan Thompson 7-5 4-6 6-3 to reach the Cincinnati Open third round on Tuesday as the world number one wobbled again in his build-up to the US Open starting later this month. An off-color Alcaraz trailed midway through the opening set, which was briefly halted by rain, but the 20-year-old recovered to break Thompson's serve having squandered eight opportunities earlier and clawed his way back to 4-4 with a hold.