Thiago Monteiro defeated Dusan Lajovic 6–4, 6–3 in the first round of the Madrid Masters on clay on 25 April 2024, recording a notable upset against the pre-match favourite. Lajovic, who carried odds of 1.57 to Monteiro's 2.55, proved unable to maintain control on the surface, conceding the opening set before a decisive second frame saw Monteiro consolidate his advantage. The Brazilian's clinical performance suggests momentum heading into the tournament's later stages, whilst Lajovic's early exit raises questions about his clay-court form at this elite level.