The 28-year-old saved seven of nine break points and broke last year’s Roland Garros runner-up on five occasions to advance after one hour and 32 minutes. Lajovic entered the match winless in five FedEx ATP Head2Head record against Thiem, but reached his second quarter-final in the past three Masters 1000 events on clay.
Thiem, the recent BNP Paribas Open champion, figured to be a strong threat in the Principality. But Lajovic took full advantage of Thiem’s deep court-positioning, playing aggressive tennis and winning some of the best rallies of the tournament thus far. Lajovic did well to consistently battle into the Austrian’s service games, winning 53 per cent of his return points in the two-setter. The Serbian was also impressive in his second-round victory against 16th seed David Goffin.
At last year’s Mutua Madrid Open, Lajovic notched five victories from qualifying to reach the last eight. Lajovic edged Juan Martin del Potro in Madrid en route to the quarter-finals before suffering a three-set loss to Kevin Anderson.
Thiem was bidding to post his 10th tour-level win of the season (9-6) and reach his second straight quarter-final at the Monte-Carlo Country Club. Thiem had reached the quarter-finals or better at five of the past seven Masters 1000 events on clay, dating back to his appearance in the last eight at the 2016 Internazionali BNL d’Italia (l. to Nishikori).
Lajovic will meet Lorenzo Sonego of Italy for a place in the semi-finals. The 23-year-old qualifier advanced to his maiden Masters 1000 quarter-final after 84 minutes, dropping only four points behind his first serve (28/32) to overcome Cameron Norrie 6-2, 7-5. Sonego is yet to drop a set in the main draw, defeating Cameron Norrie in the third round for his best result at a Masters 1000 tournament.