Lorenzo rode to victory in the Australian Grand Prix on Sunday – his third win in five races – while Marquez failed to score having been disqualified for missing his mandatory pit stop.
The race at Phillip Island was the first race to feature the compulsory stops due to tyre overheating fears, however, Marquez failed to comply inside the 10-lap deadline, allowing Lorenzo to secure the triumph and narrow the gap with two races remaining.
The Spaniard admitted they had been lucky to see his rival disqualified, but insisted retaining his title would still be very difficult.
"We have been lucky because without this (pit stop) mistake from Marc, he would have been in second or first place. He was so strong as always," the Yamaha rider said.
"Now the championship has changed so much, because before the race our options were maybe 2-3 per cent maximum, now they are 20-30 per cent.
"Anyway Marc is very competitive in all the tracks and if he finished in second or third place he will still win the championship.
"We have to try and win in both Motegi (Japan) and Valencia and then see what happens. There are a lot of racing laps left and anything can happen. We have to push every lap to the limit."
The victory was Lorenzo's sixth of the season, equalling Marquez for race wins, and moves him to 280 points for the campaign.