The world number two thus continued his impressive streak of winning sets (28) at Masters 1000 events. Recall that the previous evening, the Italian broke Novak Djokovic's record (24).
Mikkelsen put up a great fight against his favored rival, coming close to winning the second set, but in the end he had to settle for a narrow defeat.
There was no break in the first set until 5:5, when Janik broke his opponent's serve and then served for 1:0.
Much more uncertainty was seen in the second half of the game. Mikkelsen led 5:2, at 5:3 he missed a chance to take the match into the third set with his serve, but the world number two came back and fought for a tiebreak. Mikkelsen led 3:1 in the tiebreak, but Siner won the next six of seven points and finished the job in two sets, but perhaps more difficult than expected.
"I felt like my serve helped me a lot today, especially in the important moments and in the tie-break, so I'm happy about that," said Siner.
With the elimination of Carlos Alcaraz, the Italian is the main favorite to win the tournament.
"At the same time, I know that if I want to go far in this tournament, I need to improve my baseline game. Tomorrow is a day off, which suits me, so I'll try to find a good rhythm in training. We'll see how things develop later," said Janik, reflecting on the difficult conditions:
"The conditions were completely different from last night, so I'm happy with how I fought. It was very close. A very even match against Alex. He's a tough opponent, so I'm very happy."
His next opponent will be one of the two remaining Americans, Frances Tiafoe. After almost two hours of great struggle, he eliminated Frenchman Terence Atman 2:1 (6:4, 1:6, 6:4).
Tommy Paul was convincing against Argentine Tomas Martin Echeverria – 2:0 (6:1, 6:3) and thus scheduled a clash with Arturo Fiss, who in three tight sets (6:4, 6:7, 6:4) eliminated Valentin Vachero, the sensational Shanghai Masters champion.
