The 37-year-old veteran scored five goals, including the game winner with 14.5 seconds left as the Mammoth narrowly defeated the Rush 13-12 in Edmonton's home opener on Friday in the National Lacrosse League.
Grant added four assists and Adam Jones also had five goals for Colorado. Sean Pollock, Jed Prossner and Gavin Prout had the other goals for the Mammoth, who improved to 2-0 on the year.
Grant, who had an 11-point night in the Mammoth's first game against Minnesota, said his two goals to tie up the game and then win it salvaged what he thought was a pretty average night before that.
"I'm not even sure how I got in there," he said of the game-winner. "I had scored the previous couple between his legs so I went up high with that one. We were just lucky enough to get the last shot tonight. Most of the game I thought I was useless and causing a bunch of turnovers. But I was lucky enough to get one late."
With only seven returning players from last year's team, Colorado head coach Bob Hamley is happy to see his team achieve some early-season success.
"We made a lot of decisions in the off-season to go younger," he said. "One of those young guys, Adam Jones, scored five goals tonight. He's going to be a star in this league for a long time. We still have a lot of work to do but when you change out 16 players it is going to be a work in progress so it's nice to bank a couple of wins off the bat."
Ryan Ward and Zack Greer had three goals apiece for the Rush (0-1), who were the last team in the league to play a game this season.
Cory Small, with a pair of goals, and Scott Evans, Shawn Williams, Brett Mydske and Tom Johnson also scored for Edmonton.
"In the first half, even when we got up in the first quarter, we weren't very good," said Rush head coach Derek Keenan. "Our compete level was terrible. We got better in the second half. We battled back and then Grant scores a couple of goals on defensive errors. He is one of the greatest scorers every to play the game and you can't give him any room out there."
Williams, in his Edmonton debut after an off-season trade from Rochester, had eight assists in the game to go along with his goal to set a new record for most points in a game by a Rush player with nine.
"Being in Rochester for 10 years, you develop a sense of comfort, so the trade was a shock to the system at first," he said. "It was good for my head to move on and get some closure by having a good start with my new team."
Edmonton jumped out to a 2-0 lead just over two minutes in as Small scored on a bounce pass that eluded Mammoth goalie Chris Levis, followed by a nice spin-o-rama move to pick the top corner by Greer.
The Rush went up 3-0 before Colorado got on the board as a Jones shot dribbled past Edmonton goalie Aaron Bold.
Greer and Jones traded their second goals of the game for a 4-2 score at the end of the first quarter.
The Mammoth came back to tie the game up early in the second frame on a pair of soft goals by Jones and Grant.
Colorado took its first lead of the game five minutes into the second on a goal by Pollock.
The Mammoth scored two more before the end of the first half to take a 7-4 lead, outshooting the Rush 33-15 at the game's midmark.
Edmonton finally got back on the board four minutes into the third as Greer scored his third of the match.
Colorado bounced back with two more goals midway through the third, including a power-play marker by Prout.
However, the Rush came roaring back to tie the game 9-9 with four goals in under a four-minute span, including power-play markers by Williams and Ward.
Colorado went back up a goal at the end of the third with Grant's third goal of the game with just four seconds remaining.
The teams traded goals early in the fourth quarter before the Rush tied it up again on Ward's second of the game six minutes in, then took the lead on Ward's third, a short-handed goal after a long breakaway pass.
Colorado tied the game again with three minutes to play on Grant's fourth of the contest to set up the dramatic finish.
The Mammoth have very little rest before travelling to Calgary to play on Saturday. The Rush are off until Jan. 28, when they travel to Washington to play the Stealth, the first of four consecutive road games.
Notes: Both teams finished last season with 5-11 records, however, the Mammoth won their season series against the Rush to claim the fourth and final playoff spot in the West Division. ... Both teams experienced major overhauls in the off-season. The Rush have a revamped roster that includes 13 new players, while Colorado has just seven players back from last year's squad. ... Colorado got off to a good start with a 20-14 win over the Minnesota Swarm last weekend as Grant was named the NLL's offensive player of the week. Grant is currently third in NLL all-time goals. ... Edmonton came into the game 5-3 in its last eight meetings with Colorado after losing the first seven games the two teams ever played.