Lewis Hamilton opened his winning account for the new campaign in Bahrain on Sunday.

The five-time world champion took advantage of Charles Leclerc's dramatic late engine failure to take the chequered flag.

Here, Press Association Sport looks back at five things we learned from round two of the Formula One season.

1. Leclerc emerges as championship contender

Ahead of the new campaign, Ferrari indicated that Sebastian Vettel would still be their main man. For how much longer? Leclerc should have been crowned the sport's third-youngest winner in Bahrain, only to be denied by a cruel engine failure in the closing stages. At just 21, the Monegasque displayed mighty speed to put his car on pole, and then race craft beyond his tender years to fight his way back past Valtteri Bottas, and Vettel, following a poor start. Vettel has not been subjected to such a thrashing from a team-mate since Daniel Ricciardo joined Red Bull in 2014. That rivalry ended with Vettel leaving the team. Leclerc may have been hired as a number two, but his dominant display may leave Ferrari wondering whether they will have to revise their strategy.

2. What's going on with Vettel?

Given his catalogue of mistakes last year, this was always going to be a pivotal season for Vettel. But after limping to fourth in Melbourne, he was then blown away by Leclerc in Bahrain before spinning out of contention. Vettel has now spun in four of his last 10 appearances when fighting for position with a rival: Italy – Hamilton; Japan – Max Verstappen; America – Ricciardo; Bahrain – Hamilton. He also crashed out of the lead in Germany 13 races ago, and is on a winless streak which stands at 216 days. Vettel has shown he is not in the same league as Hamilton, and with Leclerc threatening to topple him as the number one at Ferrari, it would not be dramatic to say this could be the beginning of the end for the four-time world champion.

3. Hamilton knows there is work to be done

Hamilton may have snatched victory away from Leclerc to lead an improbable Mercedes one-two, but the Brit knows Sunday's result only papered over the cracks. Despite dominating the opening race in Melbourne, the Silver Arrows were second-best to Ferrari here all weekend. And Hamilton has warned that unless improvements are made, he will not be in contention a week on Sunday in China. "If they have this speed in the next race, we'll be watching them disappear," he said.

4. Bottas left in Hamilton's shade

There was a suggestion in the paddock that Bottas, who won in Australia, had returned as a meaner machine this year following a disappointing 2018. Normal service was resumed in Bahrain, however, with the Finn unable to match team-mate Hamilton. Bottas still leads the championship standings, but unlike Leclerc at Ferrari, he does not have the speed to unsettle his team-mate as the top dog at Mercedes.

5. McLaren on the march

McLaren have been subjected to plenty of stick in recent seasons, and rightly so after turning from championship contenders into also-rans. Yet, there was a noticeable air of enthusiasm around the team in Bahrain. Carlos Sainz was racing with Verstappen's Red Bull before their collision. British teenager Lando Norris then drove to sixth, to secure his first career points and McLaren's best result in more than a year. No wonder chief executive Zak Brown was all smiles as he tucked into a late-night feast at Bahrain Airport ahead of his return to London.