DHAKA: Luis Enrique's men were already five points ahead of Atletico Madrid going into the clash in Vallecas and took full advantage of their game in hand to stretch their advantage.
Having come under some early pressure from Rayo, Barca were the beneficiaries of a large stroke of fortune as a blunder from goalkeeper Juan Carlos allowed Ivan Rakitic to open the scoring in the 22nd minute.
Messi made it 2-0 after combining brilliantly with Neymar - the goal allowed to stand despite a suspicion of offside - before Rayo were reduced to 10 after Diego Llorente's foul on Rakitic, reports the sbs.com.au
A simple 53rd-minute finish saw Messi double his tally and make it 3-0, although Manucho did restore some pride for Rayo four minutes later.
The relegation-threatened hosts went down to nine men after Manuel Iturra conceded a penalty, which Suarez missed to mark Barca's seventh failure from the spot in 13 attempts, but Messi and Arda Turan completed the rout.
The hosts were given a mountain to climb just a minute later, Messi slotting into the bottom-left corner from Neymar's return pass, although replays suggested the Brazil captain may have been marginally offside when he received the initial ball down the left from the Argentina forward.
Lionel Messi scored a hat-trick as La Liga leaders Barcelona set Spanish record of 35 games unbeaten in all competitions with a 5-1 win at nine-man Rayo Vallecano, to go eight points clear at the top.
BDST: 1143 HRS, MAR 03, 2016
RS