E-commerce led the way, growing 84% during the quarter as our global digital strategy continued to deliver results.
Our two largest brands exceeded expectations with Merrell up nearly 25% year-over-year, and Saucony up nearly 60% in the quarter.
Both brands easily beat their 2019 Q1 revenue levels with Saucony up over 75% versus 2019.
The Company's international business was up 40% with every region growing over 35%.
As we look to the rest of the year, demand for our brands is very strong and we've raised our full year guidance on the strength of this demand and robust outlook.
In the first quarter, the Wolverine Michigan group revenue was up 20.1% on a reported basis and up 18.2% on a constant currency basis.
The Wolverine Boston group revenue was up 10.3% on a reported basis and up 8.2% on a constant currency basis.
Saucony grew revenue nearly 60% and expanded operating margin nearly 800 basis points in Q1, a great start to what we anticipate will be a spectacular year for the brand.
Saucony.com revenue increased by over 150% driven by compelling digital storytelling and impactful product launches.
The new Guide 14 and Kinvara 12 drove significant growth with the Guide more than doubling year-over-year.
Saucony also grew its trail running business with the launch of the Peregrine 11, which received the coveted Runner's World Editors' Choice Award.
The new Jazz Court, a sneaker made with 100% natural materials and zero plastic launched at the end of Q1, driving substantial buzz in social media and immediately becoming the brand's top-selling product on Saucony.com.
Both the new Ride 14 and Freedom 4 launched within the last few weeks and are off to a fast start.
The brand will also introduce the new Triumph 19, a follow up to the award winning predecessor.
Revenue grew nearly 25% in the quarter.
North America grew double-digits, including DTC with Merrell.com up approximately 135% and Merrell stores comping up 30%.
Merrell kicked off its Future 40 campaign at the start of the quarter, celebrating the brand's 40th anniversary and amplifying its inclusive commitment to sharing the power of the outdoors with everyone.
The brand announced a significant partnership with Big Brothers Big Sisters of America aiming to provide greater accessibility to the outdoors for nearly 200,000 youth.
In Q1, performance footwear grew by nearly 30% as the brand continued to advance its vision of faster and lighter footwear for the trail.
The Antora 2 and Nova 2 trail runners also continued to perform exceptionally well in the quarter.
Merrell's lifestyle business grew approximately 20% in the quarter driven by the growth of the classic Jungle Moc and newer hydro Moc which more than tripled year-over-year.
Our work business, which represented almost 20% of our revenue in Q1 also delivered significant growth led by Wolverine, up nearly 30% and Cat footwear up over 30% with strong contributions from a couple of our smaller brands.
Revenue was down approximately 10% in Q1, a continued sequential improvement compared to prior quarters.
Despite more than $10 million of expected revenue which slid into Q2.
During the quarter, Sperry.com was up 40% and Sperry stores grew more than 20%.
The brand's full price business remains very healthy with gross margin expanding nearly 500 basis points in Q1.
First quarter revenue of approximately $511 million represents growth of 16% compared to last year.
Adjusted gross margin improved 290 basis points versus the prior year to 44.3%, due to our continued e-commerce expansion and favorable wholesale product mix.
Adjusted selling, general and administrative expenses of $174.4 million in the quarter were about $23 million more than last year, primarily due to the higher mix of DTC revenue, $8 million of additional investment in digital e-commerce marketing and more normalized incentive compensation costs.
Q1 adjusted operating margin was 10.2%, an improvement of 330 basis points over last year, as a result of healthy operating leverage.
Net interest expense was up $1.9 million and the effective tax rate was 16%.
Adjusted diluted earnings per share were $0.40 compared to $0.28 in the prior year.
Reported diluted earnings per share were $0.45 versus $0.16 last year, and reflect a partial settlement of certain insurance claims related to our ongoing legacy litigation, offset by a legal defense costs and specific COVID related costs.
At the end of the quarter, inventory was down approximately 21% year-over-year.
In Q1, we generated $26.3 million of cash flow from operating activities.
The Company finished the quarter with $506 million less debt compared to the prior year and total liquidity of approximately $1.2 billion, including $365 million of cash on hand and nearly $800 million of revolver capacity.
Our bank defined leverage ratio continued to improve, ending the quarter at a low 1.5 times.
As a result the Company now expects fiscal 2021 revenue in the range of $2.24 billion to $2.30 billion.
Growth of 25% to 28% compared to the prior year.
At the high end of the range, this is a raise of $50 million from our original outlook and nicely exceeds 2019 revenue.
We now expect reported diluted earnings per share in the range of $1.70 to $1.85 and adjusted diluted earnings per share in the range of $1.95 to $2.10.
First, the brand's new product and marketing stories are resonating well with consumers including Sperry's Float, Merrell's Moab Speed and Moab Flight and Saucony's Guide 14, new Endorphin collections and several other new launches.
Second, our ongoing investments in digital capabilities continues to fuel e-commerce growth, which is exceeding our expectations at this early stage in the year as we track toward our bold revenue goal of $500 million through our brands.com in 2021.
The Company's strong position is a testament to our team's tremendous vigilance, focus and hard work over the last 15 months.

Summary:
As we look to the rest of the year, demand for our brands is very strong and we've raised our full year guidance on the strength of this demand and robust outlook.
Adjusted diluted earnings per share were $0.40 compared to $0.28 in the prior year.
Reported diluted earnings per share were $0.45 versus $0.16 last year, and reflect a partial settlement of certain insurance claims related to our ongoing legacy litigation, offset by a legal defense costs and specific COVID related costs.
As a result the Company now expects fiscal 2021 revenue in the range of $2.24 billion to $2.30 billion.
Growth of 25% to 28% compared to the prior year.
We now expect reported diluted earnings per share in the range of $1.70 to $1.85 and adjusted diluted earnings per share in the range of $1.95 to $2.10.