The 2018 Formula One season has already delivered uncertainty and drama by the bucket-load. Bahrain and particularly China were fantastic races with unpredictable results, stunning overtaking, flying carbon fibre, defensive and strategical masterclasses and, above all, excitement.
Given pre-season testing form and the first grand prix in Melbourne, Mercedes and Lewis Hamilton again looked clear favourites for both titles.
Mercedes, though, have had the second-quickest car in the last two races, struggling to get their tyres into the optimum operating windows and being well behind both Ferraris in qualifying. Not to mention some questionable strategy decisions on Sunday.
Elsewhere, McLaren have improved but by nowhere near enough, Marcus Ericsson scored his first points for over two years and Toro Rosso's Pierre Gasly drove to a faultless fourth in Bahrain.
What to expect as we return to the Baku City Circuit, with its narrow corners and incredibly long straight? If it's half as dramatic as last year's race then it will be quite something. Here are five reasons why it could live up to expectations.
Tyres and differing strategies
A Mercedes team member works on tyres ahead of the Formula One Azerbaijan Grand Prix in Baku on April 25, 2018
Tyre choice will play a part in deciding Sunday's race CREDIT: AFP
Three races down and by far the two most exciting of them - Bahrain and China - had massive intrigue due to differing strategies, whether through different tyre compounds or pit stops.
In Bahrain, Mercedes nearly stole a win with Valtteri Bottas hunting down Sebastian Vettel on worn tyres and Daniel Ricciardo pulling off a series of stunning overtakes in charging to victory in China on fresher tyres. This weekend could see similar, with Pirelli selecting the soft, supersoft and ultrasoft tyres as the weekend's three compounds available.
This selection is two steps softer than the sets Pirelli brought to Baku in 2017. All three compounds are viable options to be used in the race, so could we see a backmarker repeat Ericsson's feat of scoring points in Bahrain? And that's not forgetting the top three teams. Cool track conditions could also be a factor in what tyres teams choose as Mercedes have struggled with the softer sets.
The safety car could play a decisive role... again
The Safety Car on track during the Formula One Grand Prix of Singapore
The safety car has been decisive in two of 2018's three races CREDIT: GETTY IMAGES
Somewhat surprisingly, given the nature of the track, the first edition of the race in Baku two years ago saw no safety car. Last year was a different story where it appeared several times and contributed to the race's most dramatic moments before Ricciardo's eventual win.
It was under the safety car that Vettel appeared to ram Hamilton's Mercedes after the German thought his rival had brake tested him. The safety car has had a large part in deciding the outcome of two races so far in 2018. Vettel won after pitting under the virtual safety car, edging out Hamilton's quicker Mercedes. Red Bull's quick thinking in bringing both cars in under the safety car in China gave them the conditions for victory, with Ricciardo taking the top step of the podium.
Wide cars and a narrow track with tight barriers make a safety car likely in Baku. Can smart tactical thinking produce some unexpected results? Let's hope so.
A massive weekend for struggling Mercedes
Kimi Raikkonen of Finland driving the (7) Scuderia Ferrari SF71H leads Lewis Hamilton of Great Britain driving the (44) Mercedes AMG Petronas F1 Team Mercedes WO9 on track during the Formula One Grand Prix of China at Shanghai International Circuit
Mercedes have been behind Ferrari's in raw pace this year CREDIT: GETTY IMAGES
It says as much about Mercedes dominance of the turbo hybrid era (since 2014) that, until the Chinese Grand Prix a fortnight ago, they had never gone three races without winning. It also points to a 2018 season with a different look than in previous years - even last year, when Ferrari's Vettel was fighting Hamilton for the title. In fact, including the last three races of 2017 Mercedes have won just once in six races.
Admittedly, Mercedes had chances to win in all of those races but they have been in much more of a fight with Red Bull and Ferrari than ever before. It appears it could be a prolonged one. Their advantage over those teams has been at best reduced and at worst entirely removed, which means that mistakes - from the team or the drivers - become much more significant. That is what has partly caused Mercedes' results woes.
Outright performance, though, will be more of a concern. The team were well behind Ferrari on absolute pace in both Bahrain and China. Cooler conditions in Azerbaijan could hinder them again - as in China. We should have a clearer picture about the Brackley-based team's position in the pecking order come the end of the weekend.
A rejuvenated Ricciardo
Race winner Daniel Ricciardo of Australia and Red Bull Racing celebrates on the podium during the Formula One Grand Prix of China at Shanghai International Circuit on April 15,
Daniel Ricciardo won a stunning victory in China last time out, putting his team-mate in the shade CREDIT: GETTY IMAGES
When Max Verstappen drove to two late-season victories in Mexico and Malaysia last year, it was the Dutchman who had the upper hand over his Australian team-mate. Ricciardo had some excellent races in 2017, no more so than here at Baku, but he will have been disappointed with the gap to Verstappen at the end of the season.
In 2018 their form has been a huge contrast - Verstappen making costly mistakes in all three races to go with a crash in first qualifying in Bahrain. Ricciardo, meanwhile, drove from eighth on the grid to within a second of a podium in Australia, retired through an electrical failure in Bahrain and drove to a thrilling victory in China whilst Verstappen ran into Vettel and took a ten-second time penalty for his error, scuppering his chances of a victory.
The confidence will be all the Australian's, especially after Verstappen's collision with the barriers in first practice in Baku and with memories of his brilliant victory here last June. The talk in the paddock has been where the Australian will end up in 2019 but his worth has certainly risen in recent weeks with Verstappen enduring his troubles.
Flying Finns Bottas and Raikkonen
Red Bull driver Daniel Ricciardo, third from left, of Australia celebrates with Mercedes driver Valtteri Bottas, left, of Finland and Ferrari driver Kimi Raikkonen, right, of Finland on the podium after winning the Chinese Formula One Grand Prix at the Shanghai International Circuit in Shanghai,
In 2018 Bottas and Raikkonen have both fared favourably against their more successful team-mates CREDIT: AP
It is worth noting that two of the best performing (if perhaps underrated) drivers of 2018 have been Finns Valtteri Bottas for Mercedes and Raikkonen for Mercedes - certainly in comparison to their team-mates. Bottas's poor Australian Grand Prix aside, the two Finns are much closer to their team-mates than they have been and, indeed, than many expected them to be.
Bottas has out-qualified and out-finished Hamilton in the last two races whilst Raikkonen missed out on pole to Vettel by 0.143 seconds in Bahrain and by 0.087 seconds in Bahrain and has been ahead of his team-mate in most sessions this season. Race results have been mixed for Raikkonen through no fault of his own but a return to form is good news for the sport.
Bottas also tends to thrive in lower grip conditions, which has been the case in the last two races. But he has delivered in them both. Given the rumours regarding Ricciardo's 2019 seat, their performances take on added significance. Raikkonen could get that pole he's been so close to and Bottas beating Hamilton again would see him continue to answer his critics.