By Michael Butterworth

BEIJING, April 18 (Xinhua) --After a rather processional opening, Sunday's Formula One Chinese Grand Prix sprung into life after a mid-race safety car period that played perfectly into the hands of the two Red Bulls, whose lightning switch to fresh rubber laid the foundations for some of the most absorbing racing of the 2018 Formula 1 season so far. Here's what we learned from Shanghai.

1. A three-way title battle?

Much of the paddock gossip after 2018's first two races had centered on whether Ferrari had finally vaulted Mercedes to lay claim to F1's fastest car after years of playing catch-up. And when the Prancing Horse locked out the front row of the Shanghai grid by half a second, it seemed those rumors had more than a little substance. Yet there was enough evidence in Sunday's race to suggest that, under the right circumstances, Mercedes and Red Bull may be capable of going toe-to-toe with the boys from Maranello.

Though Sebastian Vettel led away from his pole position, Mercedes' Valtteri Bottas managed to squeeze ahead after the tire stops and would probably have won the race if the safety car had not been deployed. As it was, a quick double-stack Red Bull pitstop and the bunching of the pack laid the foundations for Daniel Ricciardo to take an inspired win, but of greater consequence for the rest of the season was that all three teams showed they had the pace to lead and win at various points across the weekend. With Mercedes having swept the last four drivers' and constructors' titles, long may close racing between the top three teams continue.

2. Ricciardo can afford to pick and choose

After a miserable race in Bahrain where his car ground to a halt on just the second lap, this was quite the return to form for Ricciardo. Buoyed by his fresher tires, the

Australian was in inspired form, effortlessly picking off Hamilton, Vettel and Bottas within just five laps to take arguably the best win of his career so far. With his Red Bull contract up at the end of the year, Ricciardo's sterling performance in China will have put him firmly in the shop window for possible openings at Mercedes and Ferrari for

2019, with uncertainty surrounding the futures of Bottas, Kimi Raikkonen and even possibly Lewis Hamilton, whose contract extension also remains unsigned. Speaking after the race, Ricciardo told reporters that this one victory alone would not be enough to convince him to resign with the Milton Keynes-based outfit, so if Red Bull prove unable to last the pace in this year's title fight, there remains the exciting possibility of the Honey Badger in a Mercedes or a Ferrari come 2019.

3. What's happened to Verstappen?

Ricciardo's clinical overtaking on his consummate drive to victory could not have stood in starker contrast to the struggles of his teammate Max Verstappen, who may very well have won Sunday's race instead of the Australian if it weren't for two critical errors of judgment. Handily placed in fourth after the safety car period and the critical pit stops, Verstappen then ran wide whilst trying to pass Hamilton, allowing Ricciardo through in the process. Perhaps inspired by his teammate's progress through the field, the Dutchman then attempted an excessively ambitious move on Vettel at the hairpin, which pitched both cars into a spin and saw Verstappen receive a ten-second penalty for his troubles. After finishing 2017 as arguably the field's in-form driver, the Dutchman has started 2018 in erratic fashion, and has now made four driving errors in just three race weekends. Having not long ago signed a long-term contract extension, talk of a demotion is fanciful at best, but Red Bull's management is notoriously unforgiving, and Verstappen will need to turn his season around if he is to convince the powers that be of his suitability to lead the team.

4. McLaren still struggling

Further down the field, McLaren are still not where they would like to be, even if fourth place in the constructors' championship may look like progression from last year. In reality, their lofty position owes more to the mishaps of others and Fernando Alonso's enduring ability to transcend the performance of an under-performing car. Management reshuffles and emergency debriefs have failed to provide a quick fix to McLaren's current malaise, with racing director Eric Bouiller admitting that pre-season unreliability had a detrimental effect on the car's development, and that suitable upgrades would not be seen until next month's Spanish Grand Prix. Though many have associated McLaren's struggles in recent years with the uncompetitive Honda engine, the Woking squad has not produced a car truly capable of winning races since 2012, and there are rumors that if owners the Bahraini royal family do not see a tangible improvement soon, Bouiller and CEO Zak Brown may soon be out of a job.

5. A reversal of fortunes at Mercedes

When Lewis Hamilton stormed to pole position in Melbourne while his teammate Bottas was busy clouting the wall, it seemed as if 2018 was continuing where 2017 left off, with the Finn unable to keep pace with his illustrious teammate. Since then, however, Bottas has outqualified and outraced Hamilton in both Bahrain and China, and would probably have won in Shanghai were it not for Ricciardo's banzai drive on his new Pirellis. By contrast, Hamilton seemed strangely out of sorts in China, qualifying and finishing a distant fourth, and admitting afterwards that he was racing in no-man's land. Former teammate turned pundit Nico Rosberg observed during the weekend that Hamilton's one weakness is a tendency to have off-days, and Sunday was certainly one of those, though it is unclear why the Briton appears to have lost so much pace and confidence in the car in the space of a few short weeks. Is the W09 not handling to his liking? Or are contract negotiations proving a distraction? All eyes will be on Hamilton next time out in Azerbaijan to see if he has lifted himself out of his current malaise.