Tsonga skips along the baseline and Federer is helpless as the Frenchman pings a forehand into the baseline for 30-30. Which way will the momentum swing? Well, first the pendulum moves towards the sixth seed as he earns a break point thanks to a wild and wide Tsonga forehand. But an ace comes to Tsonga's rescue and that pendulum doesn't know which way to go. A second break point comes Federer's way, though, and the Swiss earns a crucial break, with Tsonga netting a forehand.

Pulverising strike after pulverising strike from both players from the baseline.... 16 shots... 17 shots... it's Tsonga who races forward, whacking an overhead towards Federer and the Swiss nets to end the 18-shot rally. Is this where Federer begins to falter? Don't be silly. The Swiss, with the power of a bulldozer but the grace of a ballerina, comes out on top of an energetic rally, ending it with a thumping volley for another impressive hold.

Image source, Reuters

For all the superlatives thrown Federer's way in this match, credit must also be given to Tsonga who is matching the Swiss blow for blow. Federer is at his best but is unable to shake off the Frenchman.

Quick reflexes from Federer who watches the ball clip the net cord and despite the change of direction he manages to volley beyond Tsonga. Federer delving into his box of tricks and just needs to pull a rabbit out of the hat and the crowd will have seen it all. An ace from the Swiss. The second set building to a crescendo.

Rafael Nadal was angered when he was called for a second time violation by chair umpire Eva Asderaki at deuce while 4-4 at a critical time in the third set of his match against Kei Nishikori.

The Spaniard did not dispute the 20-second rule in between points at Grand Slams, but took issue with the chair umpire's handling of it.

"I don't want to change the rule. I accept that sometimes I was slow. I respect that," he said. "The negative thing in my opinion is not the warning, but the timing of it. You can choose another moment to do it, not that one.

"She didn't advise me before the second warning that I was still going slow. It's a normal thing, for the referee to help the player a little bit, and say, 'Rafa, you are going too slow'."

Catch up with the day so far in our round-up.

Men's results

Women's results

However, Nadal regained his composure to go on and clinch victory in straight sets.

Federer can sniff a whiff of a chance at 0-30. Second serve from Tsonga... the crowd quieten... nervy moments... but the Frenchman comes up with a crosscourt winner to nick back one point. Another pulverising forehand into the corner levels at 30-30. On the next point, the ball falls nicely for the Frenchman who gobbles up his chance with a double-handed backhand drive down the line. A rare error from Federer, a backhand sailing over the baseline, and Tsonga nudges ahead.

Sumptuously play from Federer who dispatches a muscly Tsonga backhand with a single-handed backhand down the line. The Swiss gliding around the court like the Federer of old and a feather-like touch at the net from the Swiss secures him another hold to love.

Tsonga sprints across the court so Federer, giving the impression he has oodles of time, nonchalantly flips a forehand winner down the line. Two big serves helps Tsonga drag himself back into contention at 30-30 and an ace to the wings - his third of the match - takes the Frenchman to within a point. The Tsonga serve on song. A fourth ace from Tsonga rapidly ends the game.

No fireworks to speak of in this game as Federer holds to love, turning the pressure back on his under-fire opponent.

Image source, AFP

Tsonga's forehand tickles the net and falls kindly for the Frenchman, dropping onto Federer's side with the Swiss stranded at the baseline. From 30-0 to 40-15, a thumping Federer forehand into the corner another indication of the Federer form. But Tsonga can match Federer for brilliance and chutzpah. From side to side they go on the baseline before Federer scoots to the tape. The Swiss looks like he could have the beating of the Frenchman, but the 10th seed also has some class at the net and conjures an irretrievable forehand winner across the court while running at full speed.

Federer simmering with a few bubbles floating up to the surface, warning us that the 17-time Grand Slam champion is ready to come to the boil. Federer again making holding serve seem like child's play.

David Law
BBC Radio 5 live sports extra commentator

"We were wondering what Stefan Edberg might bring to Federer's game and we are seeing it now in the way he is finishing rallies with such decisive shots."

Listen to live commentary on BBC Radio 5 live sports extra

No-one expected Federer to hit his stride and perform with such command in the first set, which he wrapped up in 27 minutes. The Rod Laver Arena jam-packed and the spectators transfixed as they watch this match unfold and the crowd are quickly called into action, whistling and hollering in admiration at a Tsonga smash from the baseline on the opening point. The Frenchman starts well, though Federer of course razzle-dazzles once more at the net before a dodgy return sees Tsonga hold to 30.

Jeremy Bates
Former British number one on BBC Radio 5 live sports extra

"We've not seen this form from Federer for such a long time. Everything he is doing is coming off at the moment but Tsonga is in shock. I'm sure there will be a response from Tsonga but he has to stay with Federer and not let him get ahead early in this second set. It's imperative he starts asking Federer some questions."

Listen to live commentary on BBC Radio 5 live sports extra

Luckily for Federer he doesn't have to pay a toll every time he sprints towards the net, but the ploy is working for the Swiss who has rolled back the years. He thinks we're in 2007. A super forehand winner brings up two set points and then both players watch a Tsonga lob drift long to bring an intriguing opening set to a conclusion.

Federer oozing confidence and playing with aggression. He trades power for accuracy, however, screwing a backhand wide but he makes up for that error with a glimpse of brilliance - a passing shot which leaves Tsonga floundering for 30-30. But Tsonga holds on and at least makes the sixth seed serve for the set.

Jeremy Bates
Former British number one on BBC Radio 5 live sports extra

"They have played each so many times it's like a video game in the way they read each other's shots before they have even hit them.

"This is the most aggressive I can remember Federer play. He's not giving Tsonga any time to settle into these rallies. Any time he's go the chance to take a shot on he has."

Listen to live commentary on BBC Radio 5 live sports extra

Federer is in the groove and is closing in on the first set. More delightful shot-making at the net followed by two Tsonga errors allows the Swiss to extend his advantage.

Tsonga stoops to his shoelaces and Federer can only direct the Frenchman's delicate volley long. The 10th seed gathering points a tad easier in this service game and - oof - he's clicked into gear, placing a deft volley behind his rival for a regulation hold.

Image source, Getty Images

Federer frequently visiting the net and the intimidating presence of the Swiss at the tape is causing Tsonga to spray his shots here, there and everywhere. The sixth seed races to a 40-0 lead and wraps up a hold to 15 with another foray to the net which ends with a thumping overhead. An impressive start by the 32-year-old.