He had won in Bahrain and in the season-opener in Australia, when he wasn't as dominant as Hamilton but took advantage of a safety vehicle to win on race strategy.
Bottas' late retirement in Baku handed Hamilton his first win of the season on a plate - a result that edged him ahead of Vettel in the drivers' standings for the first time this term - and he followed that up with Sunday's impressive performance.
Winning Sunday's Spanish Grand Prix may have been a turning point for Lewis Hamilton and his Mercedes Formula One team, but the champions are not counting on it.
Bottas won the 2017 season-ending Abu Dhabi Grand Prix, after an uneven first year at Mercedes following his move from Williams to replace retired 2016 world champion Nico Rosberg.
Sebastian Vettel ultimately feels Pirelli Motorsport made the right to bring updated tyre compounds with thinner treads to the Spanish Grand Prix, believing his Scuderia Ferrari team would have been even worse off had they brought the standard tyres to the Circuit de Barcelona-Catalunya.
"These different things that are coming up are going to be challenging and I don't think it's going to be as clear as it was today", said Hamilton.
"We had other priorities in the last few weeks".
"The last few laps of the race for Valtteri were very, very tense". We weren't happy with our car's performance and we needed to sort things out.
'And finalising a contract is something you need to involve yourself in and spend time and we both decided that we'd park it for a minute where we were. "But it's nearly all sorted and we'll pick it up at the right time", the Mercedes chief added.
Both Hamilton and Bottas are in contention for the driver's championship, and it is likely to remain that way for the rest of the season. Lewis Hamilton led from pole and took a dictatorial victory by 25 seconds, with his Mercedes teammate Valtteri Bottas completing a one-two for the silver squad, while Red Bull's fiery Max Verstappen punched above his weight to deny Ferrari a podium.
He said "Before I was like, "Maybe I'm just insane and everyone has got quicker and I've got slower".
"But we know as well that this was a good circuit for us and the temperatures fell in our favour as well".
And with Mercedes money men in Barcelona to witness his dominant display, Hamilton dropped the biggest hint yet that he is ready to commit his future to the German team.