Cristiano Ronaldo's thigh injury picked up during Portugal's 1-1 Euro 2020 qualifier draw with Serbia has sparked alarm in Italy ahead of Juventus's Uefa Champions League quarter-final tie against Ajax in two weeks' time. The 34-year-old Juve attacker hobbled off 30 minutes into Monday's stalemate after pulling up chasing a ball on the left wing, and Turin-based daily Tuttosport launched a "Ronaldo Alarm" on Tuesday, while <em>Gazzetta Dello Sport</em> headlined with "CR7 Worry". Juventus travel to Amsterdam for the first leg of their quarter-final clash with the Dutch side on April 10 with the return leg on April 16, and the absence of Ronaldo would be a huge blow for the Turin giants after he dragged them past Atletico Madrid in the last 16 with a return-leg hat-trick earlier this month. Recovery time for a thigh injury varies from up to 10 days for a slight problem to three months, but Ronaldo quickly moved to reassure everyone that he would soon shake off the knock. "I'm not worried. I know my body. I believe that in no more than two weeks I'll be fine," Ronaldo said. "We have to wait 24 to 48 hours." The Portuguese star is set to undergo tests on Wednesday or Thursday, either in Lisbon or at Juve's medical centre in Turin. Ronaldo was rested two weeks ago when the Italian champions suffered their first league defeat this season, 2-0 against Genoa in their last game before the international break. But Juventus have a comfortable 15-point lead on the top of the Serie A table and are on course for an eighth consecutive Scudetto. Juventus signed the five-time Champions League winner last summer for €100 million (Dh415m) to end their search for the title they last won in 1996. His hat-trick against Atletico sealed a place in the quarter-finals with a 3-2 aggregate win after being two goals down after the first leg. The five-time Ballon d'Or winner has rarely been injured during his long career. He suffered two injuries to his left ankle in 2008/09 and 2009/10, with his last serious injury a cruciate ligament sprain in his left knee during the Euro 2016 final, won by Portugal against hosts France. The Genoa defeat was the only time Juve manager Massimiliano Allegri has rested Ronaldo this season but he has other strike options available, including Argentine Paulo Dybala, who has been overshadowed by Ronaldo this season, and rising start Moise Kean, 19, fresh from scoring his first international goal with Italy against Finland.