In the anthology Shorter Novels: Elizabethan, first published in 1929, George Saintsbury writes in the introduction that the English novel had something like a false start in the Elizabethan era and that eras of great theatre did not coincide with eras of great novel writing.
He goes on to write (links and emphasis added by me),
Even later than the Restoration, things in themselves first-rate, the performances of Bunyan, Defoe, and Swift, were in the first and last cases especially, ‘side-shows’—as it were in fiction—allegories—a great word, which one might almost translate ‘side-show’ in one of its senses. (...) The ‘strong contagion’ of world-exploring which showed itself mainly in Defoe, had minor symptoms such as that curious Isle of Pines of Nevile's which the Continent, if not England, also took for history. Head's and other people's disreputable English Rogue, putting its disreputableness aside, is an attempt at a novel, and though a long one is made of short things put together: and when we come to the great quartet of the mid-eighteenth century we seem to have stumbled into competence never quite to stumble out of it again, (...).
My question is who Saintsbury has in mind when he refers to "the great quartet of the mid-eighteenth century". Daniel Defoe had died in 1731 and Jonathan Swift in 1745. Other names worth mentioning are Samuel Richardson (1689 – 1761), Henry Fielding (1707 – 1754), Laurence Sterne (1713 – 1768), Tobias Smollet (1721 – 1771) and Oliver Goldsmith (1728 – 1774). I doubt that Saintsbury was thinking of Samuel Johnson; Johnson's Rasselas is usually described as a novella. I also doubt he was thinking of Frances Brooke or John Cleland.
The problem with making a choice is that literary tastes and critical appreciation have changed since the interwar period, so any attempt to answer this question needs to look at sources from the interwar period instead of simply looking at present-day appraisals.