Messi struck in the 36th and 68th minutes of a completely one-sided match at the Nou Camp to move above Alfredo Di Stefano (227) in the record books and level with another Real Madrid legend, Raul, on 228 La Liga goals.
At just 26 years old it now seems only a matter of time before the prolific Messi claims the outright record, which is the 251 goals scored by former Athletic Bilbao star Telmo Zarra.
Hugo Sanchez is second on the list and next in Messi's sights with 234 goals for Atletico Madrid, Real Madrid and Rayo.
Rayo must be wishing they could still call on the Mexico ace as they battle to avoid relegation from the top flight this season, but even he would have been powerless to prevent the Madrid outfit from being swept aside by brilliant Barca.
Adriano opened the floodgates in just the second minute and Alexis Sanchez (53), Pedro Rodriguez (56) and a fantastic Neymar goal (89) added to Messi's double as Barca reclaimed top spot in La Liga from Atletico Madrid, who won earlier on Saturday.
The performance also fired out an ominous warning to European opponents City, who play host to Gerardo Martino's men on Tuesday night in the first leg of their last-16 tie.
Barca came into the match in buoyant mood after reaching the Copa del Rey final in midweek and they never looked like slipping up against second-bottom Rayo after Adriano had drilled in that early opener from the edge of the box.
Messi and Pedro both hit the post while the Argentina ace was also denied by a superb save from Ruben Martinez as Barca cut through Rayo's defence almost at will in the opening half-hour.
The second goal was coming and it was only a surprise that Barca had to wait so long for it to arrive, with Messi finally doubling their lead with a superb chip after Cesc Fabregas had intercepted an Anaitz Arbilla pass.
Messi then turned provider to set up Alexis for Barca's third goal soon after half-time and it was 4-0 two minutes later when Pedro slotted home following a clinical move involving two of his Spain team-mates, Andres Iniesta and Fabregas.
In between those two goals Barca goalkeeper Victor Valdes produced a fine finger-tip save to keep out Joaquin Larrivey's curling shot but that was a rare foray forward for embattled Rayo.
Messi and Dani Alves both missed chances to net before the former got his name on the scoresheet for a second time with another pinpoint finish - leaving the Argentina with 228 goals from only 263 league games. Raul, in contrast, took 550 matches to notch the same amount.
Messi, who has now scored 337 goals in all competitions for Barca, made way soon after for Cristian Tello as Martino opted to give his superstar a break ahead of the trip to Manchester, but for Rayo the misery did not end there.
Neymar, who came on in the second half having recovered from injury, added gloss to the win with the goal of the game late on, the Brazil superstar racing from halfway before smashing home an unstoppable 25-yard strike.