Youth was served in the first round of the Adelaide International on Tuesday, as teenagers Iga Swiatek and Coco Gauff claimed opening wins.

19-year-old Swiatek, the reigning Roland Garros champion from Poland, ousted qualifier Madison Brengle of the United States, 6-3, 6-4, to kick off her Adelaide campaign.

Meanwhile, 16-year-old Gauff was forced to three sets by Italy's Jasmine Paolini after failing to convert a match point in the second set, but the American ultimately won the battle of the qualifiers, 6-4, 6-7(4), 6-2.

2021 Adelaide Highlights: Gauff defeats Paolini in Round 1

No.5 seed Swiatek, coming off of her second straight appearance in the round of 16 at the Australian Open, converted all three of her break points in her 73-minute win over Brengle. Swiatek avenged a 6-1, 6-1 beatdown from Brengle in their only previous meeting, which came on the ITF Circuit in Charleston in 2018.

Read more: 'You are not a machine' - Swiatek reacts to Mikaela Shiffrin's wise words

"Madison is the kind of player who uses her opponent’s power, so I had to stay cool," Swiatek said in her on-court post-match interview. "I tried to calm myself down, stay low in the legs, and sometimes play longer rallies to get in the rhythm, because the first round is always tough at any tournament.”

Swiatek took control in the opening frame with aggressive play, slamming 11 winners to just seven unforced errors as she swept to the one-set lead.

Brengle opened up a 3-1 lead in the second set before Swiatek charged back, closing out the match with a love hold to wrap up five of the last six games. Swiatek finished the match by winning two-thirds of her second-service points as well as two-thirds of Brengle’s second service points.

Swiatek's Grand Slam winning streak ended at the hands of Simona Halep in the fourth round in Melbourne, but before that loss, she had won 10 in a row at major level dating back to her stirring title run at Roland Garros to end last season.

Said Swiatek: "Inside I’m the same person, but I realize that everybody’s kind of treating me differently, so it’s something you have to adjust to, and also keep yourself down to earth and the same as you were.

"We did a great job last year and hopefully this season will also be successful. But tennis-wise, it also changes that I’m not an underdog anymore, so I start my matches with a different attitude around, and that’s the kind of thing you have to learn to do.”

Swiatek will have to keep her attitude positive in the second round, as she is guaranteed to face a crowd favorite on home soil: qualifier Maddison Inglis, who came through an all-Australian marathon 5-7, 7-5, 6-4 over wildcard Samantha Stosur.

Inglis came from 0-3 down in the decider to outlast the 2011 US Open champion in two hours and 46 minutes, clocking in at the 10th longest match of the season so far. Afterwards, she paid tribute to her illustrious compatriot.

"I could see Sam wasn't 100% in the third so I hope everything's OK with her. It was pretty special to play with Sam, she was my idol growing up and someone I always looked up to - so to be on the same court with her was a really cool experience."

Coco Gauff, during her 2021 Adelaide International first-round match.

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Gauff, who needed a comeback win in the final round of qualifying to make the main draw, had a healthy 6-4, 5-3 lead over Paolini, but failed to serve out the match in that game, then squandered a match point at 6-4, 5-4.

Paolini took the early 5-3 lead in the second-set tiebreak and held on to level the match at one set apiece. Gauff, however, regrouped, and never dropped serve in the decider to collect the victory after two-and-a-half hard-fought hours.

Petra Martic, during her 2021 Adelaide International first-round match.

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Gauff's next opponent will be No.6 seed Petra Martic of Croatia, who also survived a barnburner in the opening round on Tuesday. Martic overcame Russian qualifier Liudmila Samsonova, 4-6, 6-0, 7-5, to set up her clash with Gauff.

After dropping the first set, Martic swept through the second set with ease and was up a double-break at 4-1 in the final set. Samsonova, though, claimed both breaks back before Martic rebounded to win eight of the final ten points.