As a result of the improved execution in both segments, year-over-year operating margins of the company improved by 800 basis points.
Our intense focus on net working capital management and improved profitability drove $40 million of positive free cash flow in the quarter, which is an excellent start to the year.
Our SG&A cost reduction initiative, with a target of full year 2021 of approximately 12.5% or better SG&A to sales remains on track.
For example, our new Genie E-Drive scissors are designed to offer significant performance improvement and reduce maintenance cost by 35% over the life of the machine.
Overall, revenues of $864 million were up 4% year-over-year.
Notably, our Materials Processing segment's revenues were up almost 20% year-over-year.
For the quarter, we recorded an operating profit of $62 million compared to an operating loss of $7 million in the first quarter of last year.
We achieved an operating margin of over 7% through disciplined cost control and meeting strengthening customer demand.
Improved gross margins and lower SG&A as a percent of sales allow Terex to expand operating margin by 800 basis points year-over-year.
Interest and other expense was approximately $4 million lower than Q1 of last year, because of several factors, including lower interest expense and a $3 million mark-to-market gain recognized in other income.
Our first quarter 2021 global effective tax rate was approximately 16%, driven by two favorable discrete items in the quarter.
Our tax rates estimate for the remainder of the year remains 19%, consistent with our previous outlook.
Finally, our reported earnings per share of $0.56 per share includes the nearly offsetting operating impact and the favorable benefits in other income that I just discussed Turning to slide nine, and our AWP segment financial results.
AWP sales of $477 million were down 7% compared to last year, driven by a decline in North America, offset by improvement in Europe and Asia-Pacific.
AWP delivered 680 basis points improvement in operating margin, which includes $3 million of severance and charges for the closure of our Oklahoma City facility.
First quarter bookings of $961 million were up to dramatically compared to Q1 2020, while backlog at quarter-end was $1.3 billion, up 82% from the prior year.
MP had another strong quarter, achieving 13% operating margins, as end markets are strengthening is a testament to the MP team's operational strength to deliver these consistent positive operating margins.
Sales were higher at $378 million, driven by improving customer sentiment across all end markets and geographies.
The MP team has been aggressively managing all elements of cost, as end markets improve resulting in incremental margin performance of 38%.
Backlog of $713 million more than doubled from last year and was up 36% sequentially.
MP saw its businesses strengthened through the quarter, with bookings up more than 100% year-over-year.
We continue to plan for incremental margins, which meet or exceed our 25% target for the full year 2021.
These transactions will result in Q2 charges of $25 million, which were not previously included in our 2021 financial outlook.
Including $0.30 per share of costs for refinancing of our capital structure, our earnings per share outlook is increased to $2.35 to $2.55 per share, based on sales of approximately $3.7 billion.
For the full year 2021, we are estimating free cash flow of approximately $150 million, reflecting another year of positive cash generation.
We continue to plan for capital expenditures, net of asset dispositions of approximately $90 million.
And finally, reduced interest expense and one-time capital structure charges of approximately $27 million, representing $0.30 per share.
Turning to page 13, and I'll review our disciplined capital allocation strategy.
The strong positive free cash flow of $40 million in the quarter demonstrates the hard work of our team members to tightly manage net working capital.
Terex has ample liquidity of approximately $1.2 billion available to us, with no near term debt maturities.
As discussed during the Q1 earnings call, the proceeds from the sale of the TFS on book portfolio and our strong liquidity position allowed us to prepay $196 million of term loans in early February.
This prepayment resulted in reducing outstanding debt, lowering, leverage, and saving annual cash interest expense of approximately $7 million.
Our refinancing included successfully renewing our $600 million revolving credit facility and placing 600 million of new bonds with a 5% coupon.
These new bonds replaced our 5.625% bonds due to mature in 2025 and reduce annual cash interest expense by approximately $4 million.

Summary:
Finally, our reported earnings per share of $0.56 per share includes the nearly offsetting operating impact and the favorable benefits in other income that I just discussed Turning to slide nine, and our AWP segment financial results.
Including $0.30 per share of costs for refinancing of our capital structure, our earnings per share outlook is increased to $2.35 to $2.55 per share, based on sales of approximately $3.7 billion.