The No. 12 seed came from two sets down for the eighth time on Tuesday, battling past big-serving Opelka 3-6, 6-7(3), 6-4, 6-3, 7-6(10/5) to reach the second round of the Australian Open for the fourth consecutive year.
The Ligurian baseliner withstood 35 aces and 60 total winners off the 22-year-old American’s racquet to advance after three hours and 38 minutes.
Rain came at the perfect time for Fognini on Monday, with Opelka up two sets to love.
The nine-time ATP Tour titlist remained calm upon the resumption of play, making just 20 unforced errors in the final three sets to force Opelka into uncomfortable backcourt rallies.
“I was lucky that the rain came on the right time,” Fognini said following his comeback.
“Yesterday he was playing better than me.
“I only lost one break, and I was two sets down.
“These guys, they’re always tough to play but we have to.”
Fognini will play Aussie Jordan Thompson tonight on Margaret Court Arena.
Fellow Italian Jannik Sinner was also victorious on Tuesday after his match was suspended due to rain on Monday.
Eighteen-year-old Sinner needed only eight points to complete his first-round win against Aussie qualifier Max Purcell on his Australian Open debut when play was suspended.
The reigning Next Gen ATP Finals champion let slip a break advantage in the third set of the match on Monday before rain washed out play for the rest of the day on the field courts.
But Sinner quickly regrouped upon returning to Court 7 on Tuesday, defeating the World No. 216 7-6(2), 6-2, 6-4 after a total of two hours and 19 minutes.
“I was up in the score, so it was a little bit easier for me. Obviously I wanted to finish yesterday,” Sinner said.
“It can be difficult.
“I tried to go on court with a good mentality, and I started well.
“That was the key.”
Sinner will face Hungarian Marton Fucsovics this afternoon.
Stefano Travaglia also resumed play on Tuesday after his match was suspended on Monday.
The Italian was losing to Chilean Cristian Garín 4-7, 3-6, 1-1 on Monday and couldn’t redeem himself on Day 2.
He was defeated 4-7, 3-6, 4-6.
Meanwile, Bolzano native Andreas Seppi was victorious, beating Serbian Miomir Kecmanović 6-4, 6-4, 7(7)-6(3).
Seppi will play World No.15, Stan Wawrinka from Switzerland, on Thursday.
Camila Giorgi brought home another win for Italy, beating Germany’s Antonia Lottner 6-3, 6-3.
Giorgi will play former World No. 2, Svetlana Kuznetsova from Russia, on Thursday.
Also on Day 2, Palermo native Marco Cecchinato failed to secure his first victory in three visits to the Australian Open, losing to German Alexander Zverev 4-6, 6(4)-7, 3-6 in two hours and 23 minutes.
Upon his victory, Zverev immediately made a pledge to donate “every single cent” of his prize money if he goes onto lift his first major trophy.
“I will donate $10,000 for every match I win here and I know I’m not the favourite to win this event, but I’ll donate every single cent to the bushfire relief fund if I win the title,”the World No.7 said.
Torinese Lorenzo Sonego also suffered a loss, going down to Aussie Nick Kyrgios 2-6, 6-7 (3-7), 6-7 (1-7).
Youngsters Elisabetta Cocciaretto and Jasmine Paolini were also kicked out of the tournament, losing to former champion Angelique Kerber and Russian Anna Blinkova respectively.