Replying to Sussex’s 301 all out, Lancashire were 339 for five at close of play with Vilas on 158 not out and Luke Wood unbeaten on 27. The most successful Sussex bowler was Ollie Robinson, who ended the day with two for 51, but the other members of Ben Brown’s attack could not match their spearhead’s excellence.
Vilas had earlier shared partnerships of 91 with Alex Davies and 125 with Rob Jones but was also given a life on 47 when George Garton failed to cling on to a diving catch at slip off Jack Carson.
However, the prosperity Lancashire enjoyed late in the evening session was a far cry from their earlier travails when they had struggled to 52 for three at lunch with England prospect Robinson taking two of the wickets. Extracting plenty of bounce and movement from the Old Trafford pitch in an eight-over spell, Robinson had Keaton Jennings taken at slip by Aaron Thomason for four and Josh Bohannon caught behind by Ben Brown for 10.
Sussex’s morning got even better when Steven Croft gloved an attempted pull off Garton to Brown and departed for three but Vilas and Davies took their side to lunch and had extended their partnership to 91, largely through a flurry of boundaries, before Davies was pinned on the back foot for 61 by Sean Hunt and thus became the debutant left-arm seamer’s maiden first-class victim.
That was Sussex’s only success of the afternoon session although off spinner Carson would have dismissed Davies for 31 had he held on to a fierce return catch and the same bowler also had Vilas dropped. As it was Carson’s first eight overs cost 50 runs, a far cry from his triumphs in last year’s Bob Willis Trophy, although he later had Rob Jones caught at backward point by Tom Clark for 58.
Having reached his century off 136 balls, Vilas took only another 53 deliveries to reach his 150 and the Sussex seamers came in for some dismissive treatment when they took the second new ball.
The teams observed two minutes' silence before the start of the afternoon session after the death of The Duke of Edinburgh was announced.