Ellis declares Holy war on Boroughmuir's bowlers
He shared in a 111-run eighth wicket partnership with the returning Manon Patel to take their side up to 238 batting first at Meggetland. Ellis made 124 and Patel 61. The hosts, who remain in relegation trouble, were then bowled out for 150 to lose by 88 runs.
The result puts Holy Cross in the title race while, elsewhere in the top flight, leaders Watsonians II, Carlton II and Fauldhouse kept up their good runs.
Opener Keith Flannigan made 97 as Watsonians II posted 280-7 battting first at Academy Park against Edinburgh II. The home side could only manage 193 all out in reply as the visitors won by 87 runs.
Ani Majumdar and Fraser Boyd scored 48 and 43 respectively as Carlton II's 255-9 was too many for Edinburgh Accies.
Fauldhouse thumped Glenrothes with opening batsmen Ashley Wallace and Derek Allan scoring 132 and 85 respectively to help the West Lothian side to 297-6. Struggling Glenrothes were then skittled for 121 with Daniel Law taking five scalps.
In Division Two there was a superb match between title chasers Marchmont and Murrayfield DAFS at Cavalry Park.
Mangesh Akerkar top scored for the visitors with 122 in their 242-8 before Matt Loeffen's 120 looked set to win the match for the hosts. His side fell just short by four runs, though, as DAFS were victorious.