MELBOURNE: Roger Federer always believed he had more Grand Slam titles left in him. He just didn't think it would happen like this, playing in his first tournament following a six-month injury layoff. Or against his biggest rival in the game, Rafael Nadal. 'I said that also before the finals: if I were to win against Rafa, it would be super special and very sweet because I haven't beaten him in a Grand Slam final for a long, long time now,' Federer said after beating Nadal in the Australian Open final 6-4, 3-6, 6-1, 3-6, 6-3. A decade, to be exact. Federer's last win over the Spaniard in a major final came at Wimbledon in 2007. Nadal had beaten him in four consecutive slam finals since then. Both Federer and Nadal also didn't expect to be in this position at the Australian Open, coming off long layoffs last season to recover from injuries. Federer has rarely missed significant stretches with injuries throughout his career. This is the man, after all, who played in a record 65 consecutive Grand Slams — a streak that was broken when he withdrew from last year's French Open with a back injury. In recent years, however, he's acknowledged making mistakes by playing through pain instead of taking time off to heal. Last year, he did things differently — he took an extended break for the first time. And after six months off to fully heal his knee, he came back stronger than ever. 'What I've just come to realise is when you don't feel well, you have too many problems going on, you just won't beat top-10 players,' Federer said after his semi-final win over Stan Wawrinka. 'That's where both, I guess, Rafa and myself said, 'OK, enough of this already. Let's get back to 100 percent, enjoy tennis again, enjoy the practice.'' Hoisting his first major trophy in five years, Federer is certainly enjoying the tennis again. Here is what else we learned from the 2017 Australian Open: Serena's next goal?: Serena Williams felt like it took a 'really long time' to win her 23rd Grand Slam title and break her tie with Steffi Graf on the all-time major winner list, so she wants to enjoy the victory and not look ahead. How about winning No. 24 and pulling even with Margaret Court, who holds the record for most major titles? She doesn't know, and doesn't want to talk about it yet. The elusive calendar year Grand Slam? 'I don't think about that either,' she said. 'Just one at a time.' The 30-fun factor: Serena proved it's possible to keep winning majors at 35 — or as she likes to call it, '30-fun.' Indeed, the 30-somethings were having fun at the Australian Open this year. Venus Williams, 36, and Mirjana Lucic-Baroni, 34, joined Serena in the semi-finals, becoming the oldest three women to reach the final four in Melbourne in the Open era. The old guard did well on the men's side, with 30-somethings Federer, Nadal and Stan Wawrinka all making the semis, too. Djokovic's slide: Novak Djokovic hasn't been himself since capturing last year's French Open. Just what's bothering him, though, remains unclear. The six-time champion seemed to lack intensity in his defeat to Uzbek wild card Denis Istomin in the second round, his earliest loss at a Grand Slam since 2008. And he was tight-lipped afterward, too. Asked what he takes away from the loss, he responded: 'Take my bags and I go home.' Second chances: It was the slam for heart-warming comeback stories. Lucic-Baroni had Rod Laver Arena in tears with her emotional interview after returning to the semi-finals of a slam for the first time in 18 years. Mischa Zverev, not his highly touted brother Alexander, pulled off one of the biggest upsets, stunning No. 1 Andy Murray. And then there's Venus Williams, back in an Australian Open final after 14 years. 'She's my inspiration,' sister Serena said. Few could disagree. Young Americans: There was much to be excited about for American tennis fans. Nine American men advanced to the second round — the most since 2008 — including promising young players Frances Tiafoe, Ernesto Escobedo and Noah Rubin. On the women's side, CoCo Vandeweghe had the tournament of her life, upsetting former major winners Angelique Kerber and Garbine Muguruza and reaching her first slam semi-final. In a post-Williams world, the future certainly looks bright.